Detailed analysis of wave motion needs a mathematical language for describing waves. Transverse waves on a string will be considered first, but the method
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A wave which travels continuously in a medium in the same direction without any change in its amplitude is called a progressive wave or a traveling wave. A progressive wave may be transverse or
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A wave which travels continuously in a medium in the same direction without any change in its amplitude is called a progressive wave or a traveling wave. A progressive wave may be transverse or
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Superposition principle states that the net disturbance at a given place and time caused by a number of waves in the same space is the vector sum of the disturbance i.e., displacements produced by
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The work done by a constant force of magnitude F on a point that moves a displacement d in the direction of the force is the product: W = Fd. Integration approach can
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Ø Energy is ability or capacity to do work. Greater the amount of energy possessed by the body, greater the work it will be able to do. Ø Energy is c
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Statement: Work done by all forces acting on a body is equal to change in its kinetic energy. Proof: Cons
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A body is said to be in tanslatory equilibrium, if net force acting on the body is zero  
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The time of doing work is called power. Power or average power is given by \({{P}_{avg}}=\frac{work\ done}{time}\) Power is a scalar
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suppose only conservative forces operate on a system of particles and potential energy U is difined correspoding to these forces. There are either no other forces or the workdone by them is
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Potential energy of a body is the enrgy possessed by a body by virtue of its position or configuration in the gravitational field. Penergy is defined only for conservative forces. It does not
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Conservative Forces: If workdone by the force around a closed path is zero and it is independent of path then it is a conservative force. Under conserva
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At boundaries between different media, there is generally both reflection and transmission. A “boundary” is a place where there is a change in “how hard it is” for the wave
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A standing wave is formed when two identical waves travelling in the opposite directions along the same line, interfere. On the path of a stationary wave, the amplitude of vibration varies simple
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A standing wave is formed when two identical waves travelling in the opposite directions along the same line, interfere. On the path of a stationary wave, the amplitude of vibration varies simple
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An ideal vibrating string will vibrate with its fundamental frequency and all harmonics of that frequency. The position of nodes and antinodes is just the opposite of
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When two sound waves of same amplitude travelling in a same direction with slightly different frequencies superimpose, then intensity varies periodically with time. This effect is called Beats. Co
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You all must have heard the whistle of a moving train. What do you feel when the train approaches you? The pitch of the whistle seems to rise. But when the engine passes by, the pitch appears to d
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COULOMB’S INVERSE SQUARE LAW:
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Electric Field : The region of space around an
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The drift velocity is the average uniform velocity acquired by free electrons inside a metal by the application of an electric field which is responsible for current through it. Free electrons
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Electric filed at the axis of a circular uniformly charged ring: Intensity of ele
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Similar to the Gauss’s law of electrostatics, this law provides us short cut methods of finding magnetic field in cases of symmetry. &nbs
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Magnetic field at the center: The distance between current element on the circular coil and the center is ‘r’ and the angle be
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If the temperature of a conductor remains constant, then the ratio of thepotential difference (or voltage) V to the current I remain constant for any conductor, which is known as resistance o
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Resistance is the property of a substance by which it opposes the flow of current through it. For a given body, the resistance is defined as the ratio of applied poten
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Resistance is the property of a substance by which it opposes the flow of current through it. For a given body, the resistance is defined as the ratio of applied poten
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a) A charged body of mass ‘m’ and charge ‘q’ is initially at rest in a uniform electric field of intensity E.  
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Electric Dipole: An electric dopole is a pair of equal and opposite point charge and seperated by a distance 2a
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ELECTRIC POTENTIAL : i) Electric potential at a point in an electric field is the amount of workdone in bringing a unit positive charge from infinity to that point
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Suppose a straight current carrying wire AB, carrying current i, lies in the plane of the paper as shown in the figure, P is a point at a perpendicular distance R from conductor, where magnetic fi
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ØTwo charges and are separated by a distance 'd'. The P.E. of the system of charges is &
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Kirchhoff's Laws for current and voltage lie at the heart of circuit analysis. With these two laws, plus the equations for individual component (resistor, capacitor, inductor), we have the bas
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A solenoid is a long cylindrical helix, which is obtained by winding closely a large number of turns of insulated copper wire over a tube of cardboard or china clay. When electric current is passe
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A solenoid is a long cylindrical helix, which is obtained by winding closely a large number of turns of insulated copper wire over a tube of cardboard or china clay. When electric current is passe
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When a charged particle having charge 'q' is projected into a magnetic field, it experiences a magnetic force which is given by the expression
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When a charged particle having charge 'q' is projected into a magnetic field, it experiences a magnetic force which is given by the expression
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An electrical cell is a device that is used to generate electricity, or one that is used to make chemical reactions possible by applying electricity. i) A c
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Consider a particle of mass m , charge q , moving horizontally with velocity u , as shown in the figure. The charge enters a region between two parallel plates (length L), where an electric field
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Consider a particle of mass m , charge q , moving horizontally with velocity u , as shown in the figure. The charge enters a region between two parallel plates (length L), where an electric field
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Consider a particle of mass m , charge q , moving horizontally with velocity u , as shown in the figure. The charge enters a region between two parallel plates (length L), where an electric field
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A current carrying conductor is itself formed by moving charges. Hence, when a current carrying conductor is placed in a magnetic field it experiences a fo
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A current carrying conductor is itself formed by moving charges. Hence, when a current carrying conductor is placed in a magnetic field it experiences a fo
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Two current carrying straight conductors placed near each other will exert (magnetic) forces on each other due to magnetic field of each other.
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Two current carrying straight conductors placed near each other will exert (magnetic) forces on each other due to magnetic field of each other.
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Case I: When place of the loop is perpendicular to magnetic field \(\ell \) &
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Case I: When place of the loop is perpendicular to magnetic field \(\ell \) &
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Introduction: When an electric current is passed through a conductor, the conductor becomes hot after some time and produce heat. This happens due to the conversion of some electric energ
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Moving coil galvanometer is an electromagnetic device that can measure small values of current. It is also known as Weston galvanometer. It works on the principle that when a current loop is place
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Moving coil galvanometer is an electromagnetic device that can measure small values of current. It is also known as Weston galvanometer. It works on the principle that when a current loop is place
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A Wheatstone bridge is an electric circuit used to measure an unknown electrical resistance by balancing two legs of a bridge circuit, one leg of which includes the unknown com
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A magnetic field line or magnetic flux line shows the direction of a magnet's force and the strength of a magnet. &
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A magnetic field line or magnetic flux line shows the direction of a magnet's force and the strength of a magnet. &
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It is the device mainly used to measure emf of a given cell and to compare emf’s of cells. It is also used to measure internal resistance of a given cell. P.D across the balancing length
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Coulomb's law, or Coulomb's inverse-square law, is a law of physics for quantifying the amount of force with which stationary electrically charged particles repel or attrac
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Coulomb's law, or Coulomb's inverse-square law, is a law of physics for quantifying the amount of force with which stationary electrically charged particles repel or attrac
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(A) If a magnet of length l and magnetic moment M gets bent in the form of a semicircular, then its new magnetic moment will &
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(A) If a magnet of length l and magnetic moment M gets bent in the form of a semicircular, then its new magnetic moment will &
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Consider the following statements : A: As no current is drawn from the cell in the secondary of a potentiometer at the t
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1.In the circuit shown in figure (a) Find the final charge on each capacitor after closing the switch. (b) &n
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INTRODUCTION: Chemistry is defined as that branch of science which deals with the composition and properties of matter and the changes that matter undergone by various interactions. A
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Motion of the body can be represented in many ways according to the vision of observer. The motion of an object is called two dimensional, if two of the three co-ordinates required specifying the
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Motion in two dimension with constant acceleration we we know is the motion in which velocity changes at a constant rate i.e, acceleration remains constant throughout the motion We should set
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Let a particle is projected from the ground with velocity u m s–1––--666565 at an angle \(\theta\) with the ground and it follow a curved path OAB as show in figure.
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CLASSIFICATION OF VIRUSES Holmes in 1948 proposed the classification of viruses. He placed all the viruses into a single order virales. Which is further divided into three sub orders as under. &
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Uniform Circular Motion If a particle moves along the circumference of a circle with constant speed, the motion is termed as uniform circular motion. Here, the magnitude of the veloci
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KINGDOM - MONERA Christesen & dougherty - gave the term ‘prokaryote’ and ‘eukaryote’ C.B. Van Neil : Divided the living organisms into prokaryotes an
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Equation of trajectory: Consider a point \(P\left( x,y \right)\) at time \(t\). Horizontal motion: Since acceleration due to gravity acts along the vertical and hence, has got no com
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Introduction The terms 'work', 'energy' and 'power' are frequently used in everyday language. A farmer clearing weeds in his field is said to be working hard. A woman c
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Introduction : The branch of botany dealing with the study of algae is called as phycology or algology. It is derived from the Greek word Phykos which means 'alga' or 'sea weed'. T
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ENERGY, TYPES OF ENERGY , CONSERVATION OF ENERGY Energy The energy of a body is defined as its capacity for doing work. (1) Since energy of a body is the total quantity of work don
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Kinetic Energy The energy possessed by a body by virtue of its motion, is called kinetic energy. Examples : (i) Flowing water possesses kinetic energy which is used to run the water mills. (
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Potential Energy Potential energy is defined only for conservative forces. In the space occupied by conservative forces every point is associated with certain energy which is called the energy of
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Law of Conservation of Energy (1) Law of conservation of energy For a body or an isolated system by work-energy theorem we have \({{K}_{2}}-{{K}_{1}}=\int_{{}}^{{}}{\vec{F}.\,d\vec{r}
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Power Power of a body is defined as the rate at which the body can do the work. Average power \(({{P}_{\text{av}\text{.}}})=\frac{\Delta W}{\Delta t}=\frac{W}{t}\) Instantaneous pow
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COLLISION ,TYPES OF COLLISIONS Collision Collision is an isolated event in which a strong force acts between two or more bodies for a short time as a result of which the energy and mom
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INTRODUCTION The term “Bryophyta” was proposed by “Robert Braun” The study of Bryophytes is known as Bryology. Hedwing is considered to be the father of Br
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Elastic head on collision and inelastic head on collision Perfectly elastic head on collision Let two bodies of masses \({{m}_{1}}\) and \({{m}_{2}}\) moving with initial velocities \(
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Introduction : The pteridophytes (Gk. Pteron = feather and phyton = plants ; means plants with feather like fronds or ferns). They are flowerless, seedless, spore producing vascular plant which ha
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Perfectly Inelastic Collision In such types of collisions, the bodies move independently before collision but after collision as a one single body. (1) When the colliding bod
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Introduction : Gymnosperm (Gk. Gymnos = naked ; sperma = seed) are the plants with exposed or naked seeds or ovules Term Gymnosperm given by Theophrastus. Study of Gymnosperm known as Gymnosp
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Introduction : The angiosperms, or flowering plants, constitute the most dominant and ubiquitous vascular plants of present day flora which changed the green and yellow melancholy of the earth's v
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Introduction : Angiospermic or flowering plants show a great variety of shape, size and form. The size ranges from the minute Wolffia and Lamna (0.1cm) to the tall Eucalyptus (up to 100 metre) and
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Chemical bond is the physical and chemical process responsible for the attractive interactions between atoms molecules, ions and that which confers stability to diatomic and polyatomic chemical entiti
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Ionic Bond or Electrovalent Bond An ion is an atom or group of atoms which has acquired charge due to the loss or gain of one or more electrons. When an atom gains an electron to form a negative io
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Bond parameters Bond Strength and Bond Length The average distance between the centres of two nuclei of the bonded atoms measured in angstrongs. Bond energy or bond strength is the amount of ene
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Covalent Bond (By Mutual Sharing of Electrons) The covalent bond is formed when two atoms achieve stability by the sharing of an electron pair, each contributing one electron to the electron pair.
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Molecular Orbital Theory Shapes of Molecular Orbitals When atomic orbital overlaps in phase then B-MO are formed and if overlaps out of phase then ABMO are formed. And both process occurs simult
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Coordinate bond, Hydrogen Bonding and Metallic Bonding Coordinate bond It is a special type of covalent bond in which both the shared electrons are contributed by one atom only. The atom which c
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Introduction Newton at the age of twenty-three is said to have seen an apple falling down from tree in his orchid. This was the year 1665. He started thinking about the role of earth's attract
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Gravitational Potential At a point in a gravitational field potential \(V\) is defined as negative of work done per unit mass in shifting a test mass from some reference point (usually at infinity)
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Kepler’s Laws of Planetary Motion Planets are large natural bodies rotating around a star in definite orbits. The planetary system of the star sun called solar system consists of ni
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INFLORESCENCE Arrangement of flower on floral axis is called inflorescence. Racemose – In this type of inflorescence the main axis continues to grow and does not terminate in a flower and
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TISSUE: A group of cells which is having similar or dissimilar in shape, having a common origin and usually performing a common function is called tissue. The term tissue was coined by Nehe
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Heat, Temperature and its measurements Introduction William Thomson, 1st Baron Kelvin, (1824 –1907) was a British mathematical physicist, engineer, and outstanding leader in the
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Thermal Expansion Most substance expand when they are heated. Thermal expansion is a consequence of the change in average separation between the constituent atoms of an object. Atoms of a
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Ideal Gas Equation and Absolute Temperature Concept of an Ideal gas A gas has no shape and size and can be contained in a vessel of any size or shape. It expands indefinitely and unifo
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Conduction The process of transmission of heat energy in which the heat is transferred from one particle to other particle without dislocation of the particle from their equilibrium position is cal
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Convection Mode of transfer of heat by means of migration of material particles of medium is called convection. It is of two types. (1) Natural convection: This arise due to differ
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What is Lorem Ipsum? Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknow
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Count and compare the number of atoms of each element on the LHS and RHS of the arrow. Is the number of atoms of each element the same on both the sides? If yes, then the equation is balanced. If not,
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electricity has an important place in modern society. It is a controllable and convenient form of energy for a variety of uses in homes, schools, hospitals, industries, and so on. What constitutes ele
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We are familiar with air current and water current. We know that flowing water constitute water current in rivers. Similarly, if the electric charge flows through a conductor (for example, through a m
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law of reflection is defined as In the case of dielectrics such as glass, the electric field of the light acts on the electrons in the material, and the moving electrons generate fields and beco
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WHAT ARE CELESTIAL BODIES How wonderful it is to watch the sky after sunset! One would first notice one or two bright dots shining in the sky. Soon you would see the number increasing. You cannot c
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STARS AND CONSTELLATIONS Stars Some celestial bodies are very big and hot. They are made up of gases. They have their own heat and light, which they emit in large amounts. These celestial bodies
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PLANETS Some celestial bodies do not have their own heat and light. They are lit by the light of the stars. Such bodies are called planets. The word ‘planet’ comes from the Greek word &
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THE SUN The sun, eight planets, satellites, and some other celestial bodies known as asteroids and meteoroids form the solar system. We often call it a solar family, with the sun as its Head.
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PLANETS There are eight planets in our solar system. In order of their distance from the sun, they are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
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THE MOON A Satellite A Satellite is a celestial body that moves around the planets in the same way as the planets move around the sun. Our earth has only one satellite, that is, the
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ASTEROIDS & METEOROIDS Asteroids Apart from the stars, planets, and satellites, there are numerous tiny bodies which also move around the sun. These bodies are called asteroids. They are fou
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GALAXY & UNIVERSE Galaxy Do you see whitish broadband, like a white glowing path across the sky on a clear starry night? It is a cluster of millions of stars. This band is the Milky Way
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GLOBE AND AXIS Globe In the previous chapter, you have read that our planet earth is not a sphere. It is slightly flattened at the North and the South Poles and bulge in the middle. Can you imag
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EQUATOR Another imaginary line running on the globe divides it into two equal parts. This line is known as the equator. The northern half of the earth is known as the Northern Hemisphere and the so
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PARALLELS OF LATITUDES All parallel circles from the equator up to the poles are called parallels of latitudes. Latitudes are measured in degrees. The equator represents the zero-degre
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IMPORTANT PARALLELS OF LATITUDES Besides the equator (0°), the North Pole (90°N), and the South Pole (90° S), there are four important parallels of latitudes– 1.Tropic of Cance
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TORRID, TEMPERATE & FRIGID ZONES Torrid Zone The mid-day sun is exactly overhead at least once a year on all latitudes in between the Tropic of Cancer and the Tropic of Capricorn. This area,
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WHAT ARE LONGITUDES? To fix the position of a place, it is necessary to know something more than the latitude of that place. You can see, for example, that Tonga Islands (in the Pacific Ocean) and
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PRIME MERIDIAN Unlike parallels of latitude, all meridians are of equal length. Thus, it was difficult to number the meridians. Hence, all countries decided that the count should begin from the mer
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LONGITUDE AND TIME The best means of measuring time is by the movement of the earth, the moon, and the planets. The sun regularly rises and sets every day, and naturally, it is the best time-keeper
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WHY DO WE HAVE STANDARD TIME? The local time of places which are on different meridians is bound to differ. For example, it will be difficult to prepare a time-table for trains which cross several
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WHAT IS ROTATION? As you know that the earth has two types of motions, namely rotation, and revolution. Rotation is the movement of the earth on its axis. The axis of the earth which i
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WHAT IS REVOLUTION? The movement of the earth around the sun in a fixed path or orbit is called Revolution. (or) The secon
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SUMMER SOLSTICE On 21st June, the Northern Hemisphere is tilted towards the sun. The rays of the sun fall directly on the Tropic of Cancer. As a result, these areas receive more heat. The areas nea
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WINTER SOLSTICE On 22nd December, the Tropic of Capricorn receives direct rays of the sun as the South Pole tilts towards it. As the sun’s rays fall vertically at the Tropic of Capricorn (23&
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EQUINOX On 21st March and September 23rd, direct rays of the sun fall on the equator. At this position, neither of the poles is tilted towards the sun; so, the whole earth experiences equal days an
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WHAT ARE MAPS? You have learnt in the previous chapter about the advantages of a globe. However, the globe has limitations as well. A globe can be useful when we want to study the earth as a whole.
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PHYSICAL, POLITICAL AND THEMATIC MAPS Maps provide more information than a globe. They are of different types. Some of them are described below. Physical maps Maps showing natural features of
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DISTANCE There are three Components of Maps – distance, direction, and symbol. Distance Maps are drawings, which reduce the entire world or a part of it to fit on a sheet of paper
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DIRECTION Most maps contain an arrow marked with the letter ‘N’ at the upper right-hand corner. This arrow shows the north direction. It is called the north line. When you know the nort
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SYMBOLS It is the third important component of a map. It is not possible to draw on a map of the actual shape and size of different features such as buildings, roads, bridges, trees, rail
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SKETCH AND PLAN Sketch A sketch is a drawing mainly based on memory and spot observation and not to scale. Sometimes a rough drawing is required of an area to tell where a partic
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INTRODUCTION As you have read in the first chapter, the earth is the only planet that has life. Human beings can live here because the life-sustaining elements of land, water, and air are pres
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BIOSPHERE – THE DOMAIN OF LIFE The Biosphere is the narrow zone where we find land, water, and air together, which contains all forms of life. (Or) The biosphere is the narrow zone of c
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LITHOSPHERE – CONTINENTS AND OCEANS BASINS Lithosphere The solid portion of the earth is called the Lithosphere. It comprises the rocks of the earth’s crust and the thin layers of so
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ASIA, EUROPE Asia is the largest continent. It covers about one-third of the total land area of the earth. The continent lies in the Eastern Hemisphere. The Tropic of Cancer passes through this con
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AFRICA Africa is the second-largest continent after Asia. The Equator or 00 latitude runs almost through the middle of the continent. A large part of Africa lies in the Northern Hemisphere. Look at
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NORTH AMERICA AND SOUTH AMERICA North America is the third largest continent in the world. It is linked to South America by a very narrow strip of land called the Isthmus of Panama. The continent l
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AUSTRALIA AND ANTARCTICA Australia is the smallest continent that lies entirely in the Southern Hemisphere. It is surrounded on all sides by the oceans and seas. It is called an island co
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HYDROSPHERE The earth is called the blue planet. More than 71 percent of the earth is covered with water and 29 percent is with the land. Hydrosphere consists of water in all its&nbs
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OCEAN Oceans are a major part of the hydrosphere. They are all interconnected. The ocean waters are always moving. The three chief movements of ocean waters are the waves, the tides, and the ocean
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ATMOSPHERE AND ITS COMPONENTS The earth is surrounded by a layer of gas called the atmosphere. This thin blanket of air is an integral and important aspect of the planet. It provides us with the ai
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INTERNAL AND EXTERNAL PROCESS These landforms are a result of two processes. You will be amazed to know that the ground you are standing on is slowly moving. Within the earth, a continuous movement
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MOUNTAINS Broadly, we can group different landforms depending on elevation and slope as mountains, plateaus, and plains. A hill is a land surface that rises higher than the surrounding area. Gen
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PLATEAUS A plateau is an elevated flat land. It is a flat-topped table land standing above the surrounding area. A plateau may have one or more sides with steep slopes. The height of plateaus often
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PLAINS Plains are large stretches of flat land. They are, generally, not more than 200 meters above mean sea level. Some plains are extremely level. Others may be slightly rolling and undulating. M
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PEOPLE IN DIFFERENT LANDFORMS Humans have been living in different kinds of landforms in different ways. Life is difficult in mountainous areas. Plains provide much better conditions. It is easy to
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LOCATION OF INDIA India is a country of vast geographical expanse. In the north, it is bound by the lofty Himalayas. The Arabian Sea in the west, the Bay of Bengal in the east, and the Indian Ocean
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OUR NEIGHBOURS There are seven countries that share land boundaries with India. Across the sea to the south, lie our island neighbors— Sri Lanka and the Maldives. Sri Lanka is separated from
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POLITICAL AND ADMINISTRATIVE DIVISIONS India is a vast country. For administrative purposes, the country is divided into 29 States and 9 Union Territories. Delhi is the national capital. The states
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PHYSICAL DIVISIONS India is marked by a diversity of physical features such as mountains, plateaus, plains, coasts, and islands. Standing as sentinels in the north are the lofty snow-c
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WHAT IS WEATHER OR CLIMATE? You read in newspapers daily and watch on T.V. or hear others talking about the weather. You must know that weather is about day to day changes in the atmosphere. It inc
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WINTER Cold weather season *Cold Weather Season (Winter) December to February. *During the winter season, the sun rays do not fall directly in the region. As a result, the temperatures are qu
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SUMMER Hot weather season * Hot Weather Season (Summer) March to May. * In the hot weather season sun rays more or less directly fall in this region. Temperature becomes very high.
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RAINY SEASON Southwest monsoon season * Southwest Monsoon Season (Rainy) June to September. * This season is marked by the onset and advance of the monsoon. The winds blow from Ara
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AUTUMN Season of retreating monsoons * Season of Retreating Monsoon (Autumn) October and November. * Winds move back from the mainland to the Bay of Bengal. This is the season of t
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WHAT IS NATURAL VEGETATION? The climate of a place is affected by its location, altitude, distance from the sea, and relief. Therefore, we experience regional differences in the climate of India. J
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WHY ARE FORESTS NECESSARY? Forests are very useful for us. They perform various functions. Plants release oxygen that we breathe and absorb carbon dioxide. The roots of the plants bind the soil; th
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WILDLIFE Forests are home to a variety of wildlife. There are thousands of species of animals and a large variety of reptiles, amphibians, mammals, birds, insects, and worms which dwell in the fore
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STORY OF PAST Finding out what happened Yesterday: you could listen to the radio, watch television, read a newspaper. Last year: ask somebody who remembers. But what about long, long ago?
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BANKS OF NARMADA, INDUS AND GANGA Find the river Narmada on Map 1. People have lived along the banks of this river for several hundred thousand years. Some of the earliest people who lived here
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SULAIMAN, KIRTHAR, GARO HILLS AND VINDYAS Now find the Sulaiman and Kirthar hills to the northwest. Some of the areas where women and men first began to grow crops such as wheat and barley abou
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WHY DO PEOPLE TRAVEL NOWADAYS? Hills, mountains, and seas form the natural frontiers of the subcontinent. While it was difficult to cross these frontiers, those who wanted could and did scale the m
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NAMES OF THE LAND Two of the words we often use for our country are India and Bharat. The word India comes from the Indus, called Sindhu in Sanskrit. The Iranians and the Greeks who came through t
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MANUSCRIPTS There are several ways of finding out about the past. One is to search for and read books that were written long ago. These are called manuscripts because they were written by hand (thi
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INSCRIPTIONS We can also study inscriptions. These are writings on relatively hard surfaces such as stone or metal. Sometimes, kings got their orders inscribed so that people could see, read and ob
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ARCHEOLOGY There were many other things that were made and used in the past. Those who study these objects are called archaeologists. They study the remains of buildings made of stone and brick,
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OUR PASTS Did you notice the title of this book, Our Pasts? We have used the word ‘pasts’ in the plural to draw attention to the fact that the past was different for different groups of
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BC AND AD If somebody asks you the date, you will probably mention the day, month, and year, 2000 and something. These years are counted from the date generally assigned to the birth of Jesus
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STORY OF HUNTER-GATHERS The earliest people: why were they on the move? We know about people who lived in the subcontinent as early as two million years ago. Today, we describe them as hunter
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FINDING HUNTER-GATHERS Archaeologists have found some of the things hunter-gatherers made and used. It is likely that people made and used tools of stone, wood, and bone, of which stone tools have
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EVIDENCE OF HUNTER-GATHERS Look at Map below. All the places marked with red triangles are sites from which archaeologists have found evidence of hunter-gatherers. (Hunter-gatherers lived in many m
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ROCK PAINTINGS Many of the caves in which these early people lived have paintings on the walls. Some of the best examples are from Madhya Pradesh and southern Uttar Pradesh. These paintings show wi
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FINDING OUT ABOUT FIRE Traces of ash have been found in Kurnool caves. This suggests that people were familiar with the use of fire. Fire could have been used for many things: as a source of light,
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PALAEOLITHIC Archaeologists have given lengthy names for the time that we are studying. They call the earliest period the Palaeolithic. This comes from two Greek words, ‘palaeo’, meanin
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MESOLITHIC The period when we find environmental changes, beginning about 12,000 years ago till about 10,000 years ago is called the Mesolithic (middle stone). Stone tools found during this period
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NEOLITHIC The next stage, from about 10,000 years ago, is known as the Neolithic. What do you think the term Neolithic means? We have also mentioned the names of some places. You will find th
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A CHANGING ENVIRONMENT Around 12,000 years ago, there were major changes in the climate of the world, with a shift to relatively warm conditions. In many areas, this led to the development of grass
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START OF FARMING AND HERDING This was also a time when several grain bearing grasses, including wheat, barley, and rice grew naturally in different parts of the subcontinent. Men, women, and c
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DOMESTICATION Beginnings of domestication (about 12,000 years ago). Domestication is the name given to the process in which people grow plants and look after animals. Very often, plants and anim
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GROWING PLANTS AND STORING ANIMALS If you plant a seed, you will notice that it takes some time to grow. This may be for several days, weeks, months, and in some cases years. When people began
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FINDING FIRST FARMERS AND HERDERS Turn to Map. You will notice a number of blue squares. Each marks a site from where archaeologists have found evidence of early farmers and herders. These are foun
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TOWARDS A SETTLED LIFE Archaeologists have found traces of huts or houses at some sites. For instance, in Burzahom (in present-day Kashmir) people built pit-houses, which were dug into the ground,
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LIVING AND DYING IN MEHRGARH Beginning of settlement at Mehrgarh (about 8000 years ago). Mehrgarh is located in a fertile plain, near the Bolan Pass, which is one of the most important rout
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A STORY TO TELL Very often, old buildings have a story to tell. Nearly a hundred and fifty years ago, when railway lines were being laid down for the first time in Punjab, engineers stumbled upon t
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SPECIAL ABOUT THESE CITIES Many of these cities were divided into two or more parts. Usually, the part to the west was smaller but higher. Archaeologists describe this as the citadel. Generally, th
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HOUSES, DRAINS AND STREETS Generally, houses were either one or two storeys high, with rooms built around a courtyard. Most houses had a separate bathing area, and some had wells to supply water.
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LIFE IN THE CITY A Harappan city was a very busy place. There were people who planned the construction of special buildings in the city. These were probably the rulers. It is likely that the rulers
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NEW CRAFTS IN THE CITY Let us look at some of the objects that were made and found in Harappan cities. Most of the things that have been found by archaeologists are made of stone, shell, and metal,
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IN SEARCH OF RAW MATERIALS Raw materials are substances that are either found naturally (such as wood, or ores of metals) or produced by farmers or herders. These are then processed to produce fini
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FOOD FOR PEOPLE IN THE CITIES While many people lived in the cities, others living in the countryside grew crops and reared animals. These farmers and herders supplied food to craftspersons, scribe
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A CLOSER LOOK The city of Dholavira was located on Khadir Beyt (also spelled as Bet) in the Rann of Kutch, where there were freshwater and fertile soil. Unlike some of the other Harappan cities, wh
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THE MYSTERY OF THE END Around 3900 years ago we find the beginning of a major change. People stopped living in many of the cities. Writing, seals and weights were no longer used. Raw materials brou
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ONE OF THE OLDEST BOOKS IN THE WORLD You may have heard about the Vedas. There are four of them – the Rigveda, Samaveda, Yajurveda, and Atharvaveda. Activity: Find out whether you
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SAGES AND SUKTA The oldest Veda is the Rigveda, composed about 3500 years ago. The Rigveda includes more than a thousand hymns, called sukta or “well-said”. These hymns are in praise of
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HOW HISTORIANS STUDY THE RIGVEDA Historians, like archaeologists, find out about the past, but, in addition to material remains, they examine written sources as well. Let us see how they study the
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CATTLE, HORSES AND CHARIOTS There are many prayers in the Rigveda for cattle, children (especially sons), and horses. Horses were yoked to chariots that were used in battles, which were fought to c
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WORDS TO DESCRIBE PEOPLE There are several ways of describing people — in terms of the work they do, the language they speak, the place they belong to, their family, their communities, and cu
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THE STORY OF THE MEGALITHS Look at the Figure below. These stone boulders are known as megaliths (literally big stones). These were carefully arranged by people and were used to mark burial
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FINDING OUT ABOUT SOCIAL DIFFERENCES Archaeologists think that objects found with a skeleton probably belonged to the dead person. Sometimes, more objects are found in one grave than in another. In
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FAMILY BURIAL SPOTS Sometimes, megaliths contain more than one skeleton. These indicate that people, perhaps belonging to the same family, were buried in the same place though not at the same time.
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A SPECIAL BURIAL AT INAMGAON Inamgaon is a site on the river Ghod, a tributary of the Bhima. It was occupied between 3600 and 2700 years ago. Here, adults were generally buried in the ground, laid
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OCCUPATIONS AT INAMGAON Archaeologists have found seeds of wheat, barley, rice, pulses, millets, peas, and sesame. Bones of a number of animals, many bearing cut marks that show they may have been
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HOW SOME MEN BECAME RULERS? Choosing leaders or rulers by voting is something that has become common during the last fifty years or so. How did men become rulers in the past? Some of the rajas we r
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VARNAS We have many books that were composed in north India, especially in the areas drained by the Ganga and the Yamuna, during this period. These books are often called later Vedic because they w
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JANAPADAS The rajas who performed these big sacrifices were now recognized as being rajas of janapadas rather than Janas. The word janapada literally means the land where the Jana set its foot and
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MAHAJANAPADAS About 2500 years ago, some janapadas became more important than others and were known as mahajanapadas. Some of these are shown on Map. Most mahajanapadas had a capital city, many of
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TAXES As the rulers of the mahajanapadas were (a)building huge forts (b) maintaining big armies, they needed more resources. And they needed officials to collect these. So, instead of depending on
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CHANGE IN AGRICULTURE There were two major changes in agriculture around this time. One was the growing use of iron ploughshare. This meant that heavy, clayey soil could be turned over better than
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MAGADHA Magadha became the most important mahajanapada in about two hundred years. Many rivers such as the Ganga and Son flowed through Magadha. This was important for (a) transport, (b) water supp
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VAJJI While Magadha became a powerful kingdom, Vajji, with its capital at Vaishali (Bihar), was under a different form of government, known as Gana or sangha. In a gana or a sangha there were no
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AJATASTTU AND THE VAJJIS This is an account of the Vajjis from the Digha Nikaya, a famous Buddhist book, which contains some of the speeches of the Buddha. These were written down about 2300 years
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FROM SIDDHARTHA TO BUDDHA Siddhartha, also known as Gautama, the founder of Buddhism, was born about 2500 years ago. This was a time of rapid change in the lives of people. As you saw in Chapter 5(
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BUDDHA TEACHINGS The Buddha taught that life is full of suffering and unhappiness. This is caused because we have cravings and desires (which often cannot be fulfilled). Sometimes, even if we get w
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THE STORY OF KISAGOTAMI Here is a famous story about the Buddha. Once there was a woman named Kisagotami, whose son had died. She was so sad that she roamed through the streets of the city carry
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SIX SCHOOLS OF INDIAN PHILOSOPHY Over centuries, India’s intellectual exploration of truth has come to be represented by six systems of philosophy. These are known as Vaishesika, Nyaya, Samkh
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UPANISHADS Around the time that the Buddha was preaching and perhaps a little earlier, other thinkers also tried to find answers to difficult questions. Some of them wanted to know about life after
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JAINISM The last and 24th tirthankara of the Jainas, Vardhamana Mahavira, also spread his message around this time, i.e. 2500 years ago. He was a kshatriya prince of the Lichchhavis, a group that w
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THE SANGHA Both the Mahavira and the Buddha felt that only those who left their homes could gain true knowledge. They arranged for them to stay together in the sangha, an association of those who l
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MONASTERIES To begin with, both Jaina and Buddhist monks went from place to place throughout the year, teaching people. The only time they stayed in one place was during the rainy season, when it w
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THE SYSTEM OF ASHRAMAS Around the time when Jainism and Buddhism were becoming popular,brahmins developed the system of ashramas. Here, the word ashrama does not mean a place where people live a
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AN EMPIRE The lions that we see on our notes and coins have a long history. They were carved in stone and placed on top of a massive stone pillar at Sarnath (about which you read in Chapter 6(
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RULING THE EMPIRE As the empire was so large, different parts were ruled differently. The area around Pataliputra was under the direct control of the emperor. This meant that officials were appoint
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THE EMPEROR AND THE CAPITAL CITY Megasthenes was an ambassador who was sent to the court of Chandragupta by the Greek ruler of West Asia named Seleucus Nicator. Megasthenes wrote an account abou
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ASHOKA, A UNIQUE RULER The most famous Mauryan ruler was Ashoka. He was the first ruler who tried to take his message to the people through inscriptions. Most of Ashoka’s inscriptions were in
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ASHOKA’S KALINGA WAR AND INSCRIPTION Kalinga is the ancient name of coastal Orissa. Ashoka fought a war to conquer Kalinga. However, he was so horrified when he saw the violence and bloodshed
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WHAT WAS ASHOKAS’S DHAMMA Ashoka’s dhamma did not involve the worship of a god, or performance of a sacrifice. He felt that just as a father tries to teach his children, he had a duty t
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ASHOKA’S MESSAGES “People perform a variety of rituals when they fall ill when their children get married when children are born, or when they go on a journey. These rituals are not
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TOOLS AND TRANSPLANTATION We often take the use of iron for granted today. Things made of iron (and steel) are a part of our daily lives. The use of iron began in the subcontinent around 3000 years
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THE VILLAGE HEADMAN There were at least three different kinds of people living in most villages in the southern and northern parts of the subcontinent. In the Tamil region, large landowners were k
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STORIES AND TRAVELLERS You may have heard of the Jatakas. These were stories that were probably composed by ordinary people, and then written down and preserved by Buddhist monks. Here is part of
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SCULPTURE AND ARCHAEOLOGY We can use other kinds of evidence to find out about life in some of these early cities. Sculptors carved scenes depicting peoples’ lives in towns and villages, as
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COINS You may have noticed how wealth is measured in terms of coins in the story (The clever poor man). Archaeologists have found several thousands of coins belonging to this period. The earliest
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MATHURA – AN EXAMPLE Very often, a single town was important for a variety of reasons. Let us look at the example of Mathura (see in Map). Mathura has been an important settlement for
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ARCHAEOLOGICAL EVIDENCE FOR CRAFTS We also have archaeological evidence for crafts. These include extremely fine pottery, known as the Northern Black Polished Ware (NBPW). It gets its name from th
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RULES FOR SPINNING AND WEAVING These rules are from the Arthashastra, mentioned in Chapter 7(ASHOKA, THE EMPEROR WHO GAVE UP WAR). They describe how spinning and weaving could be done in workshops
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ARIKAMEDU – ITS CLOSER LOOK Between 2200 and 1900 years ago, Arikamedu was a coastal settlement where ships unloaded goods from distant lands. A massive brick structure, which may have been
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EVIDENCE OF TRADE AND TRADERS You read about the Northern Black Polished Ware in Chapter 8(VITAL VILLAGES, THRIVING TOWNS). This fine pottery, especially bowls and plates, were found from several a
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STORY OF CHOLAS, CHERAS, AND PANDYAS The southern half of the subcontinent is marked by a long coastline, and with hills, plateaus, and river valleys. Amongst the river valleys, that of the Kaveri
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SATAVAHANAS Around 200 years later a dynasty known as the Satavahanas became powerful in western India (see Map). The most important ruler of the Satavahanas was Gautamiputra Shri Satakarni. We kno
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INVENTION OF SILK The rich, glossy colours of silk, as well as its smooth texture, make it a highly valued fabric in most societies. Making silk is a complicated process. Raw silk has to be extract
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SILK ROUTE Look at Map which shows the Silk Route and its branches. Some kings tried to control large portions of the route. This was because they could benefit from taxes, tributes, and gifts that
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FROM BIOGRAPHY TO STATUES The most famous Kushana ruler was Kanishka, who ruled around 1900 years ago. He organised a Buddhist council, where scholars met and discussed important matters. Ashvag
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BODHISATTVAS The second change was a belief in Bodhisattvas. These were supposed to be persons who had attained enlightenment. Once they attained enlightenment, they could live in complete iso
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JOURNEY OF FA XIAN, XUAN ZANG, AND I-QING As traders journeyed to distant lands in caravans and ships, pilgrims often travelled with them. The best-known of these are the Chinese Buddhist pilgri
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NALANDA – A UNIQUE LEARNING CENTER Xuan Zang and other pilgrims spent time studying in Nalanda, (Bihar) the most famous Buddhist monastery of the period. This is how he describes it: &ldqu
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IDEA OF BHAKTI This was also the time when the worship of certain deities, which became a central feature of later Hinduism, gained in importance. These deities included Shiva, Vishnu, and goddesse
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BHAKTI AND POEM BY A BHAKTA Bhakti Bhakti comes from the Sanskrit term bhaj meaning ‘to divide or share.’ This suggests an intimate, two-way relationship between the deity and the de
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SAMUDRAGUPTA’S PRASHASTI Arvind was supposed to be acting as Samudragupta, a famous ruler of a dynasty known as the Guptas. We know about Samudragupta from a long inscription, inscribed on th
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SAMUDRAGUPTA’S POLICIES If you look at Map, you will notice an area shaded in green. You will also find a series of red dots along the east coast. And you will find areas marked in purple an
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GENEALOGIES Most prashastis also mention the ancestors of the ruler. This one mentions Samudragupta’s great grandfather, grandfather, father and mother. His mother, Kumara Devi, belonged to t
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BIOGRAPHY – THE HARSHACHARITA While we can learn about the Gupta rulers from their inscriptions and coins, we can find out about some kings from biographies. Harshavardhana, who ruled nearly
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PALLAVAS VS CHALUKYAS The Pallavas and Chalukyas were the most important ruling dynasties in south India during this period. The kingdom of the Pallavas spread from the region around their capital,
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PULAKESHIN II BIOGRAPHY The best-known Chalukya ruler was Pulakeshin II. We know about him from a prashasti, composed by his court poet Ravikirti. This tells us about his ancestors, who are traced
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STEPS ADOPTED As in the case of earlier kings, land revenue remained important for these rulers, and the village remained the basic unit of administration. There were some new developments a
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A NEW KIND OF ARMY Like earlier rulers, some of these kings maintained a well-organised army, with elephants, chariots, cavalry and foot soldiers. Besides, there were military leaders who provided
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ASSEMBLIES The inscriptions of the Pallavas mention a number of local assemblies. These included the sabha, which was an assembly of brahmin landowners. This assembly functioned through subcommitte
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ORDINARY PEOPLE We can catch an occasional glimpse of the lives of ordinary people from plays, and other accounts. Let us look at some of these. 1. Kalidasa is known for his plays depicting life
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THE KING’S ARMY Banabhatta provides us with a vivid picture of the king’s army on the move: The king travelled with an enormous amount of equipment. Apart from weapons, there were th
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ARCHAEOLOGICAL EXCAVATIONS Ancient Indian metallurgists made major contributions to the metallurgical history of the world. Archaeological excavations have shown that the Harappans were master craf
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THE IRON PILLAR ON PILLAR The iron pillar at Mehrauli, Delhi, is a remarkable example of the skill of Indian craftspersons. It is made of iron, 7.2. m high, and weighs over 3 tonnes. It was made ab
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STUPAS The skills of our craftspersons are also apparent in the buildings that have survived, such as stupas. The word stupa means a mound. While there are several kinds of stupas, round and tall,
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GARBHAGRIHA, SHIKHARA AND MANDAPA Some of the earliest Hindu temples were also built at this time. Deities such as Vishnu, Shiva, and Durga were worshipped in these shrines. The most important part
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AN EXPENSIVE AFFAIR There were several stages in building a stupa or a temple. Usually, kings or queens decided to build these as it was an expensive affair. First, the good quality stone had to be
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PAINTING Ajanta is a place where several caves were hollowed out of the hills over centuries. Most of these were monasteries for Buddhist monks, and some of them were decorated with paintings. Here
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SILAPPADIKARAM AND MANIMEKALAI Some of the best–known epics were written during this period. Epics are grand, long compositions, about heroic men and women, and include stories about gods.
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MEGHADUTA Other writers, such as Kalidasa, (about whom you read in Chapter 10(NEW EMPIRES AND KINGDOMS)) wrote in Sanskrit. Here is a verse from Kalidasa’s best-known poem, the Meghaduta,
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RECORDING AND PRESERVING OLD STORIES A number of Hindu religious stories that were in circulation earlier were written down around the same time. These include the Puranas. Purana literally means o
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STORIES BY ORDINARY PEOPLE – THE MONKEY KING Ordinary people also told stories, composed poems and songs, sang, danced, and performed plays. Some of these are preserved in collections of stor
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WRITING BOOKS ON SCIENCE This was also the time when Aryabhata, a mathematician, and astronomer, wrote a book in Sanskrit known as the Aryabhatiyam. He stated that day and night were caused by the
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WHAT IS DIFFERENCE AND PREJUDICE? There are many things that make us what we are – how we live, the languages we speak, what we eat, wear, the games we play, and the things we celebrate. A
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CREATING STEREOTYPES All of us are familiar with gender differences. What does it mean to be a boy or a girl? Many of you would say, "We are born as boys and girls. It is a given. What is ther
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REASONS FOR INEQUALITY AND DISCRIMINATION Discrimination happens when people act on their prejudices or stereotypes. If you do something to put other people down, if you stop them from taking part
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ON BEING DISCRIMINATED AGAINST People are engaged in different kinds of work like teaching, carpentry, pottery, weaving, fishing, farming, etc. to earn a livelihood. However, certain kinds of work
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ABOUT BHIM RAO AMBEDKAR Dr. Bhim Rao Ambedkar (1891-1956) is considered the father of the Indian Constitution and is also the best-known leader of the Dalits. Dr. Ambedkar fought for the rights of
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SAD JOURNEY OF AMBEDKAR Dr. Bhimrao Ambedkar, one of the greatest leaders of India, shares his first experience of caste-based discrimination, which took place in 1901 when he was just nine years o
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INEQUALITY VS EQUALITY The struggle for freedom from British rule also included within it the struggle of large groups of people who not only fought against the British but also fought to be treate
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LIFE ON THE STREET There are more than five thousand towns and twenty-seven big cities in India. Big cities like Chennai, Mumbai, Delhi, Kolkata, etc. have more than a million people living and wor
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LIFE OF BACHCHU MANJHI I, BACHCHU MANJHI come from a village in Bihar where I worked as a mason. My wife and three children live in the village. We don't own land. In the village, I did not get
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VENDORS AND SERVICES Provide a service Like Bachchu Manjhi a large number of people in the city work on the streets. In a survey of Ahmedabad city, it was found that 12 percent of all the worker
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IN THE MARKET When we reached the market the shops were just beginning to open. But the place was already crowded because of the festival season. There were rows and rows of shops selling sweets, t
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HARPREET AND VANDANA: BUSINESSPERSONS My father and uncle worked in a small shop. During festival times and on Sundays my mother and I helped them in the shop. I started working there only after I
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IN THE FACTORY – WORKSHOP AREA I wanted to have zari work done on one of my dresses which I needed for a special occasion. My cousin said that she knew Nirmala who works in a garment factory.
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WORKS IN THE OFFICE My aunt, Sudha works as a Marketing Manager. She had asked us to reach her office before 5.30 p.m. We thought we'd get late so we took an autorickshaw that managed to get us
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ABOUT KALPATTU VILLAGE Kalpattu is a village that's close to the sea coast in Tamil Nadu. People here do many kinds of work. As in other villages, here too there is non-farm work such as making
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THULASI All of us here work on Ramalingam's land. He has twenty acres of paddy fields in Kalpattu. Even before I was married I used to work on paddy fields in my parental village. I work from 8
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SEKAR We have to carry this paddy to our house. My family has just finished harvesting our field. We don't own much land, only two acres. We manage to do all the work on our own. At times, espe
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RAMALINGAM AND KARUTHAMMA In addition to land, Ramalingam’s family owns a rice mill and a shop selling seeds, pesticides, etc. For the rice mill, they used some of their own money and also bo
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ON BEING IN DEBT As you've read previous topics, very often farmers like Sekar need to borrow money to purchase basic things like seeds, fertilisers, and pesticides. Often they borrow this mone
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FAMILIES OF AGRICULTURAL LABOURERS AND FARMERS In Kalpattu village there are agricultural labourers like Thulasi, and many small farmers like Sekar, and a few big farmers like Ramalingam. In India,
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ARUNA AND PAARIVELAN In the coastal areas, we find fishing villages. Let us find out more about the lives of a fishing family by reading about Aruna and Paarivelan who live in Pudupet, a village cl
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RURAL LIVELIHOODS People in rural areas earn their living in various ways. Some work on farms while others earn their living on non- farm activities. Working on farms involves operations such as pr
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ROLE OF URBAN ADMINISTRATION A city is much bigger than a village and more spread out. A city has crowded markets, many buses and cars, water and electricity facilities, traffic control, and hospit
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THE WARD COUNCILLOR AND ADMINISTRATIVE STAFF "Yasmin Khala, I'm curious. Who decides where a park should go to? Did you have to make interesting decisions like this when you worked in the
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HOW DOES THE MUNICIPAL CORPORATION GET ITS MONEY? Providing and running so many services requires a lot of money. The Municipal Corporation collects this in different ways. A tax is a sum of money
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GANGABAI’S STORY Yasmin Khala continued, "The women were very unhappy about the situation and even came to me for advice. I said I could try and speak with some officers in the dep
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PALGUE SCARE IN SURAT The city of Surat had a plague scare in 1994. Surat was one of the dirtiest cities in India. Houses, hotels, and restaurants would dump their garbage into the nearest drain or
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A QUARREL IN THE VILLAGE Mohan is a farmer. His family owns a small agricultural field, which they have been farming for many years. Next to his field is Raghu's land which is separated from hi
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AREA OF THE POLICE STATION On the way to the police station, one of the neighbours asked, "Why don't we spend some more money and go to the main police station in the town?" "
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THE WORK AT THE POLICE STATION When they reached the police station Mohan went to the person in charge (Station House Officer or S.H.O.) and told him what had happened. He also said that he wanted
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MAINTENANCE OF LAND RECORDS Measuring land and keeping land records is the main work of the Patwari. The Patwari is known by different names in different states - in some villages, such officers ar
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SUPERVISION OF PATWARI WORKS Keeping track of all the crops grown in this area, organising the collection of land revenue from the farmers is the work of the revenue department of the government. S
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A NEW LAW (Hindu Succession Amendment Act, 2005) Often when we think of farmers who own land, we think of men. Women are seen as people who work in the fields, but not as people who own agricult
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WHAT IS GRAM SABHA? The Gram Sabha is a meeting of all adults who live in the area covered by a Panchayat. This could be only one village or a few villages. In some states, as in the example above,
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PROBLEMS USUALLY DISCUSSED It's a special day today! Everyone's rushing to get to the Gram Sabha! Do you know why? Because the Gram Sabha is holding its first meeting after the electi
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ROLE OF THE GRAM PANCHAYAT The Gram Panchayat meets regularly and one of its main tasks is to implement development programmes for all villages that come under it. As you have seen, the work of the
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THREE LEVELS OF PANCHAYATS After reading about what happened in the Gram Sabha and the Gram Panchayat in Hardas village you can understand that the Panchayati Raj System is a process through which
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NELSON MANDELA VS APARTHEID LAWS South Africa is a country that has people of several races. There are black people who belong to South Africa, whites who came there to settle, and Indians who came
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PARTICIPATION Why do we have regular elections? You've already read in the previous chapter that people make decisions in a democracy. Through voting in elections, people elect leaders to repre
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OTHER WAYS OF PARTICIPATING Elections are usually held once in five years. Besides voting, there are other ways of participating in the process of government. People participate by taking an intere
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ROLE OF GOVERNMENT In Maya's story, you read about how conflicts can often lead to violence and death because one group decides that it is all right to use force to prevent the other group from
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EQUALITY AND JUSTICE One of the key ideas of a democratic government is its commitment to equality and justice. Equality and justice are inseparable. The earlier practice of untouchability is no
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ROLE OF GOVERNMENT Every country needs a government to make decisions and get things done. These can be decisions about where to build roads and schools, or how to reduce the price of onions when t
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LAWS AND THE GOVERNMENT The government makes laws and everyone who lives in the country has to follow these. This is the only way governments can function. Just like the government has the power to
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LOCAL, STATE AND CENTRAL LEVEL Now that you know that the government is responsible for so many different things, can you think of how it manages to do all these? The government works at different
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DEMOCRACY VS MONARCHY Who gives the government this power to make decisions and enforce laws? The answer to this question depends on the type of government there is in a country. In a democracy,
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DEMOCRATIC GOVERNMENTS India is a democracy. This achievement is the result of a long and eventful struggle of the Indian people. There are other places in the world where people have also struggle
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WHAT IS DIVERSITY? Look around you in the classroom: do you see anyone who looks exactly like you do? In this topic, you will learn that people are different from each other in many ways. Not only
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A NEW PAPER STORY Do you think it would be easy for you to make friends with someone who was very different from you? Read the following story and think about this. I had meant it as a joke. A j
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JOURNEY OF SAMIR EK AND SAMIR DO While Samir Ek is more familiar with English, Samir Do speaks Hindi. Although they both are more at home in different languages they still communicated with each ot
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WHY SAMIR DO A PAPERBOY? Samir Do did not have the opportunity to attend school. Perhaps you've noticed that there are several people in the area where you live who are poor and who don't h
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STORIES THAT TEACH Just like Samir Ek and Samir Do became friends, you might have friends who are very different from you. You have probably eaten different kinds of food in their homes, celebrated
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INTERMIXING OF CULTURES India is a country of many diversities. We speak different languages, have various types of food, celebrate different festivals, practice different religions. But actually,
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HISTORICAL AND GEOGRAPHICAL FACTORS The history of many places shows us how many different cultural influences have helped to shape life and culture there. Thus regions became very diverse because
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INDIA’S UNITY IN DIVERSITY India's diversity has always been recognised as a source of its strength. When the British ruled India, women, and men from different cultural, religious, and r
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INTRODUCTION In Class IX we have learnt that matter around us is present in the form of elements, compounds, and mixtures and the elements contain atoms of only one type. Do you know h
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Why Classify Elements? We have been learning how various things or living beings can be classified on the basis of their properties. Even in other situations, we come across instances o
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Döbereiner’s Triads About Johann Wolfgang Döbereiner (1780-1849) Johann Wolfgang Döbereiner studied as a pharmacist at Münchberg in Germany, and then studied chemis
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ART OF FREDERIC SORRIEU In 1848, Frederic Sorrieu, a French artist, prepared a series of four prints visualising his dream of a world made up of ‘democratic and social Republics’, as he
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THE FRENCH REVOLUTION The first clear expression of nationalism came with the French Revolution in 1789. France, as you would remember, was a full-fledged territorial state in 1789 under the rule o
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Newlands’ Law of Octaves The attempts of Döbereiner encouraged other chemists to correlate the properties of elements with their atomic masses. In 1866, John Newlands, an English scienti
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HISTORY OF EUROPE What we know today as Germany, Italy, and Switzerland were divided into kingdoms, duchies and cantons whose rulers had their autonomous territories. Eastern and Central Europe wer
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THE ARISTOCRACY AND THE NEW MIDDLE CLASS Socially and politically, a landed aristocracy was the dominant class on the continent. The members of this class were united by a common way of life that c
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WHAT DID LIBERAL NATIONALISM STAND FOR? Ideas of national unity in early-nineteenth-century Europe were closely allied to the ideology of liberalism. The term ‘liberalism’ derives from
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A NEW CONSERVATISM AFTER 1815 Following the defeat of Napoleon in 1815, European governments were driven by a spirit of conservatism. Conservatives believed that established, traditional institutio
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THE REVOLUTIONARIES During the years following 1815, the fear of repression drove many liberal-nationalists undergrounds. Secret societies sprang up in many European states to train revolutionaries
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TREATY OF CONSTANTINOPLE As conservative regimes tried to consolidate their power, liberalism and nationalism came to be increasingly associated with the revolution in many regions of Europe such a
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THE ROMANTIC IMAGINATION AND NATIONAL FEELING The development of nationalism did not come about only through wars and territorial expansion. Culture played an important role in creating the idea of
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MAKING ORDER OUT OF CHAOS – MENDELEEV’S PERIODIC TABLE About Dmitri lvanovich Mendeléev (1834-1907) Dmitri lvanovich Mendeléev was bor
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HUNGER, HARDSHIP AND POPULAR REVOLT The 1830s were years of great economic hardship in Europe. The first half of the nineteenth century saw an enormous increase in population all over Europe. In mo
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1848: THE REVOLUTION OF THE LIBERALS Parallel to the revolts of the poor, unemployed and starving peasants and workers in many European countries in the year 1848, a revolution led by the educated
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LIBERTY AND EQUALITY OF WOMEN How were liberty and equality for women to be defined? The liberal politician Carl Welcker, an elected member of the Frankfurt Parliament, expressed the following v
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GERMANY – CAN THE ARMY BE THE ARCHITECT OF A NATION? After 1848, nationalism in Europe moved away from its association with democracy and revolution. Nationalist sentiments were often mobilis
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ITALY UNIFIED Like Germany, Italy too had a long history of political fragmentation. Italians were scattered over several dynastic states as well as the multi-national Habsburg Empire. During the m
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THE STRANGE CASE OF BRITAIN The model of the nation or the nation-state, some scholars have argued, is Great Britain. In Britain, the formation of the nation-state was not the result of a sudden up
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Achievements of Mendeleev’s Periodic Table While developing the Periodic Table, there were a few instances where Mendeléev had to place an element with a slightly greater atomic mass b
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ALLEGORY OF THE NATION While it is easy enough to represent a ruler through a portrait or a statue, how does one go about giving a face to a nation? Artists in the eighteenth and nineteenth centuri
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BALKAN – THE ORIGIN OF FIRST WORLD WAR By the last quarter of the nineteenth-century nationalism no longer retained its idealistic liberal-democratic sentiment of the first half of the centur
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LIMITATIONS OF MENDELEEV’S CLASSIFICATION The electronic configuration of hydrogen resembles that of alkali metals. Like alkali metals, hydrogen combines with halogens, oxygen, and sulphur to
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MAKING ORDER OUT OF CHAOS – THE MODERN PERIODIC TABLE In 1913, Henry Moseley showed that the atomic number (symbolised as Z) of an element is a more fundamental property than i
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Position of Elements in the Modern Periodic Table The Modern Periodic Table has 18 vertical columns known as ‘groups’ and 7 horizontal rows known as ‘periods’. Let us see wh
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VALENCY As you know, the valency of an element is determined by the number of valence electrons present in the outermost shell of its atom. Activity 5.6 How do you calculate the valency of an
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ATOMIC SIZE The term atomic size refers to the radius of an atom. The atomic size may be visualised as the distance between the centre of the nucleus and the outermost shell of an isolated atom. T
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METALLIC AND NON-METALLIC PROPERTIES As we can see, the metals like Na and Mg are towards the left-hand side of the Periodic Table while the non-metals like sulphur and chlorine are found
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ROLE OF ACIDS, BASES AND SALTS IN OUR DAILY LIFE You have learnt in your previous classes that the sour and bitter tastes of food are due to acids and bases, respectively, present in them
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ROSE OF NATIONALISM IN INDIA As you have seen, modern nationalism in Europe came to be associated with the formation of nation-states. It also meant a change in people’s understanding of who
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UNDERSTANDING THE CHEMICAL PROPERTIES OF ACIDS AND BASES Acids and Bases in Laboratory Activity 2.1 Collect the following solutions from the science laboratory– hydrochloric acid (HCl),
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How do Acids and Bases React with Metals? Activity 2.3 CAUTION: This activity needs the teacher’s assistance. Set the apparatus as shown in Fig. 2.1. &n
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FORCED RECRUITMENT In the years after 1919, we see the national movement spreading to new areas, incorporating new social groups, and developing new modes of struggle. How do we understand these de
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How do Metal Carbonates and Metal Hydrogen carbonates React with Acids? Activity 2.5 Figure 2.2: Passing carbon dioxide gas through a calcium hydroxide solution Take two test tubes,
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THE IDEA OF SATYAGRAHA Mahatma Gandhi returned to India in January 1915. As you know, he had come from South Africa where he had successfully fought the racist regime with a novel method of ma
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How do Acids and Bases React with each other? Activity 2.6 Take about 2 mL of dilute NaOH solution in a test tube and add two drops of phenolphthalein solution. What is the colour of the solu
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How do Acids and Bases React with each other? Activity 2.6 Take about 2 mL of dilute NaOH solution in a test tube and add two drops of phenolphthalein solution. What is the colour of the solu
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THE ROWLATT ACT Emboldened with this success, Gandhiji in 1919 decided to launch a nationwide satyagraha against the proposed Rowlatt Act (1919). This Act had been hurriedly passed through the Impe
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The Reaction of Metallic Oxides with Acids Activity 2.7 Take a small amount of copper oxide in a beaker and add dilute hydrochloric acid slowly while stirring. Note the colour of the solution
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WHY NON-COOPERATION? In his famous book, Hind Swaraj (1909) Mahatma Gandhi declared that British rule was established in India with the cooperation of Indians, and had survived only becau
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THE MOVEMENT IN THE TOWNS The Non-Cooperation-Khilafat Movement began in January 1921. Various social groups participated in this movement, each with its own specific aspiration. All of them respon
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REBELLION IN THE COUNTRYSIDE From the cities, the Non-Cooperation Movement spread to the countryside. It drew into its fold the struggles of peasants and tribals which were developing in diffe
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SWARAJ IN THE PLATATIONS Workers too had their own understanding of Mahatma Gandhi and the notion of swaraj. For plantation workers in Assam, freedom meant the right to move freely in and out of th
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The Reaction of a Non-metallic Oxide with Base You saw the reaction between carbon dioxide and calcium hydroxide (lime water) in Activity 2.5. Once we shall revise the Activity 2.5. &n
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WHAT DO ALL ACIDS AND ALL BASES HAVE IN COMMON? In Section 2.1 we have seen that all acids have similar chemical properties. We saw in Activity that all acids generate hydrogen gas on reacti
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THE INDEPENDENCE DAY PLEDGE,26 JANUARY 1930 In February 1922, Mahatma Gandhi decided to withdraw the Non-Cooperation Movement. He felt the movement was turning violent in many places and satyagrahi
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THE SALT MARCH AND THE CIVIL DISOBEDIENCE MOVEMENT Mahatma Gandhi found in salt a powerful symbol that could unite the nation. On 31 January 1930, he sent a letter to Viceroy Irwin statin
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What Happens to an Acid or a Base in a Water Solution? Do acids produce ions only in an aqueous solution? Let us test this. Activity 2.9 &
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HOW PARTICIPANTS SAW THE MOVEMENT? Let us now look at the different social groups that participated in the Civil Disobedience Movement. Why did they join the movement? What were their ideals? What
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HOW STRONG ARE ACID OR BASE SOLUTIONS? We know how acid-base indicators can be used to distinguish between an acid and a base. We have also learnt in the previous section about dilution and a decre
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THE LIMITS OF CIVIL DISOBEDIENCE Not all social groups were moved by the abstract concept of swaraj. One such group was the nation’s ‘untouchables’, who from around the 1930s had
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Importance of pH in Everyday Life Are plants and animals’ pH sensitive? Our body works within the pH range of 7.0 to 7.8. Living organisms can survive only in a narrow range of p
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Family of Salts In the previous sections, we have seen the formation of salts during various reactions. Let us understand more about their preparation, properties, and uses. Activity 2.13 Wri
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pH of Salts Activity 2.14 Collect the following salt samples – sodium chloride, potassium nitrate, aluminium chloride, zinc sulphate, copper sulphate, sodium acetate, sodium carbonate and
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COLLECTIVENESS IN MAKING NATIONALISM Nationalism spreads when people begin to believe that they are all part of the same nation, when they discover some unity that binds them together. But how did
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CONCLUSION A growing anger against the colonial government was thus bringing together various groups and classes of Indians into a common struggle for freedom in the first half of the twentieth cen
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QUIT INDIA MOVEMENT The failure of the Cripps Mission and the effects of World War II created widespread discontentment in India. This led Gandhiji to launch a movement calling for the complete wit
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Chemicals from Common Salt By now you have learnt that the salt formed by the combination of hydrochloric acid and sodium hydroxide solution is called sodium chloride. This is the salt that you use
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Are the Crystals of Salts really Dry? Activity 2.15 Figure 2.9 Removing water of crystallisation Heat a few crystals of copper sulphate in a dry boiling tube. What is t
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Review on Elements learnt in IX Class In Class IX you have learnt about various elements. You have seen that elements can be classified as metals or non-metals on the basis of their properties
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METALS The easiest way to start grouping substances is by comparing their physical properties. Let us study this with the help of the following activities. For performing Activities 3.1 to 3.6, col
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NON-METALS In the previous Class, you have learnt that there are very few non-metals as compared to metals. Some of the examples of non-metals are carbon, sulphur, iodine, oxygen, hydroge
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THE PRE-MODERN WORLD When we talk of ‘globalisation’ we often refer to an economic system that has emerged since the last 50 years or so. But as you will see in this chapter, the making
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SILK ROUTES LINK THE WORLD The silk routes are a good example of vibrant pre-modern trade and cultural links between distant parts of the world. The name ‘silk routes’ points to the imp
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FOOD TRAVELS: SPAGHETTI AND POTATO Food offers many examples of long-distance cultural exchange. Traders and travellers introduced new crops to the lands they travelled. Even ‘ready’ fo
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CONQUEST, DISEASE AND TRADE The pre-modern world shrank greatly in the sixteenth century after European sailors found a sea route to Asia and also successfully crossed the western ocean to America.
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CHANGES OF WORLD IN NINETEENTH CENTURY The world changed profoundly in the nineteenth century. Economic, political, social, cultural and technological factors interacted in complex ways to transfor
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A WORLD ECONOMY TAKES SHAPE A good place to start is the changing pattern of food production and consumption in industrial Europe. Traditionally, countries liked to be self-sufficient in food. But
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ROLE OF TECHNOLOGY What was the role of technology in all this? The railways, steamships, the telegraph, for example, were important inventions without which we cannot imagine the transformed ninet
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LATE NINETEENTH-CENTURY COLONIALISM Trade flourished and markets expanded in the late nineteenth century. But this was not only a period of expanding trade and increased prosperity. It is important
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RINDERPEST, OR THE CATTLE PLAGUE In Africa, in the 1890s, a fast-spreading disease of cattle plague or rinderpest had a terrifying impact on people’s livelihoods and the local economy. This i
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INDENTURED LABOUR MIGRATION FROM INDIA The example of indentured labour migration from India also illustrates the two-sided nature of the nineteenth-century world. It was a world of faster economic
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INDIAN ENTREPRENEURS ABROAD Growing food and other crops for the world market required capital. Large plantations could borrow it from banks and markets. But what about the humble peasant?  
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INDIAN TRADE, COLONIALISM AND THE GLOBAL SYSTEM Historically, fine kinds of cotton produced in India were exported to Europe. With industrialisation, British cotton manufacture began to e
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CHEMICAL PROPERTIES OF METALS We will learn about the chemical properties of metals in the following Sections 3.2.1 to 3.2.4. For this, collect the samples of the following metals &n
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What happens when Metals react with Water? Activity 3.10 CAUTION: This Activity needs the teacher’s assistance. Collect the samples of the same metals as in Activity 3.9. Put small p
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What happens when Metals react with Acids? You have already learnt that metals react with acids to give salt and hydrogen gas. Metal + Dilute acid \(\to \) &
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How do Metals react with Solutions of other Metal Salts? Activity 3.12 Figure 3.4 The reaction of metals with salt solutions Take a clean wire of copper and an iron nail. Put the
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The Reactivity Series The reactivity series is a list of metals arranged in the order of their decreasing activities. After performing displacement experiments (Activities 1.9 and 3.12),
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HOW DO METALS AND NON-METALS REACT? In the above activities, you saw the reactions of metals with a number of reagents. Why do metals react in this manner? Let us recall what we learnt about the el
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Properties of Ionic Compounds Activity 3.13 Take samples of sodium chloride, potassium iodide, barium chloride or any other salt from the science laboratory. What is the p
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WARTIME TRANSFORMATIONS The First World War (1914-18) was mainly fought in Europe. But its impact was felt around the world. Notably, for our concerns in this chapter, it plunged the first half of
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POSTWAR RECOVERY Post-war economic recovery proved difficult. Britain, which was the world’s leading economy in the pre-war period, in particular faced a prolonged crisis. While Britain was p
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RISE OF MASS PRODUCTION AND CONSUMPTION In the US, recovery was quicker. We have already seen how the war helped boost the US economy. After a short period of economic trouble in the years aft
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CORROSION You have learnt the following about corrosion in Chapter 1 – Silver articles become black after some time when exposed to air. This is because it reacts with sulphur i
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THE GREAT DEPRESSION The Great Depression began around 1929 and lasted till the mid-1930s. During this period most parts of the world experienced catastrophic declines in production, employment, in
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PREVENTION OF CORROSION The rusting of iron can be prevented by painting, oiling, greasing, galvanising, chrome plating, anodising or making alloys. Galvanisation is a method
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INDIA AND THE GREAT DEPRESSION If we look at the impact of the depression on India we realise how integrated the global economy had become by the early twentieth century. The tremors of a crisis in
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POST –WAR RECONSTRUCTION The Second World War broke out a mere two decades after the end of the First World War. It was fought between the Axis powers (mainly Nazi Germany, Japan, and Italy)
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IMPORTANCE OF CARBON IN DAILY LIFE In the last Chapter, we came to know many compounds of importance to us. In this chapter, we will study some more interesting compounds and their properties. Also
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POST- WAR SETTLEMENT AND BRETTON WOODS INSTITUTIONS Economists and politicians drew two key lessons from inter-war economic experiences. First, an industrial society based on mass production cannot
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THE EARLY POST-WAR YEARS The Bretton Woods system inaugurated an era of unprecedented growth of trade and incomes for the Western industrial nations and Japan. World trade grew annually at over 8 p
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DECOLONISATION AND INDEPENDENCE When the Second World War ended, large parts of the world were still under European colonial rule. Over the next two decades most colonies in Asia and Africa emerged
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END OF BRETTON WOODS AND THE BEGINNING OF ‘GLOBALISATION’ Despite years of stable and rapid growth, not all was well in this post-war world. From the 1960s the rising costs of its overs
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BONDING IN CARBON – THE COVALENT BOND In the previous chapter, we have studied the properties of ionic compounds. We saw that ionic compounds have high melting and boiling points an
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INNOVATION AND CHANGES In 1900, a popular music publisher E.T. Paull produced a music book that had a picture on the cover page announcing the ‘Dawn of the Century’ (Fig. 1). As you can
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PROTO- INDUSTRIALISATION All too often we associate industrialisation with the growth of the factory industry. When we talk of industrial production we refer to factory production. When we talk of
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THE COMING UP OF THE FACTORY The earliest factories in England came up by the 1730s. But it was only in the late eighteenth century that the number of factories multiplied. The first symbol of t
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MOLECULES FORMED BY SHARING VALENCE ELECTRONS Before going on to compounds of carbon, let us look at some simple molecules formed by the sharing of valence electrons. Formation of Hydr
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THE PACE OF INDUSTRIAL CHANGE How rapid was the process of industrialisation? Does industrialisation mean only the growth of factory industries? First: The most dynamic industries in Britain wer
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ALLOTROPY: Allotropes of Carbon The element carbon occurs in different forms in nature with widely varying physical properties. Both diamond and graphite are formed by carbon atoms, the differen
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NEED OF HAND LABOUR In Victorian Britain, there was no shortage of human labour. Poor peasants and vagrants moved to the cities in large numbers in search of jobs, waiting for work. As you will kno
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VERSATILE NATURE OF CARBON We have seen the formation of covalent bonds by the sharing of electrons in various elements and compounds. We have also seen the structure of a simple carbon c
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LIFE OF THE WORKERS The abundance of labour in the market affected the lives of workers. As news of possible jobs travelled to the countryside, hundreds tramped to the cities. The actual possibilit
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THE AGE OF INDIAN TEXTILES Let us now move to India to see how a colony industrialises. Once again we will look not only at factory industries but also at the non-mechanised sector. We will limit o
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Saturated and Unsaturated Carbon Compounds We have already seen the structure of methane. Another compound formed between carbon and hydrogen is ethane with a formula of C2H6. In order to
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WHAT HAPPENED TO WEAVERS? The consolidation of East India Company power after the 1760s did not initially lead to a decline in textile exports from India. British cotton industries had not yet expa
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MANCHESTER COMES TO INDIA In 1772, Henry Patullo, a Company official, had ventured to say that the demand for Indian textiles could never reduce since no other nation produced goods of the same qua
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Chains, Branches and Rings In the earlier section, we mentioned the carbon compounds methane, ethane, and propane, containing respectively 1, 2, and 3 carbon atoms. Such ‘chains’ of car
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THE EARLY ENTREPRENEURS The first cotton mill in Bombay came up in 1854 and it went into production two years later. By 1862 four mills were at work with 94,000 spindles and 2,150 looms. Around th
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Will you be my Friend? Carbon seems to be a very friendly element. So far we have been looking at compounds containing carbon and hydrogen only. But carbon also forms bonds with other elemen
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WHERE DID THE WORKERS COME FROM? Factories needed workers. With the expansion of factories, this demand increased. In 1901, there were 584,000 workers in Indian factories. By 1946 the number was o
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EXPORTS AND IMPORTS European Managing Agencies, which dominated industrial production in India, were interested in certain kinds of products. They established tea and coffee plantations, acquiring
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Homologous Series You have seen that carbon atoms can be linked together to form chains of varying lengths. These chains can be branched also. In addition, a hydrogen atom or other atoms on these c
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SMALL SCALE INDUSTRIES PREDOMINATE While factory industries grew steadily after the war, large industries formed only a small segment of the economy. Most of them – about 67 percent in 1911 &
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ROLE OF ADVERTISEMENTS We have seen how British manufacturers attempted to take over the Indian market, and how Indian weavers and craftsmen, traders and industrialists resisted colonial controls,
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Nomenclature of Carbon Compounds The names of compounds in a Homologous Series are based on the name of the basic carbon chain modified by a “prefix” “phrase before&rdqu
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CONCLUSION Clearly, the age of industries has meant major technological changes, growth of factories, and the making of a new industrial labour force. However, as you have seen, hand technology and
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Combustion Carbon, in all its allotropic forms, burns in oxygen to give carbon dioxide along with the release of heat and light. Most carbon compounds also release a large amount of heat
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Why do substances burn with or without a flame? Have you ever observed either a coal or a wood fire? If not, the next time you get a chance, take close note of what happens when the wood
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Formation of coal and petroleum Coal and petroleum have been formed from biomass which has been subjected to various biological and geological processes. Coal is the remains of trees, fer
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HISTORY OF PRINTING It is difficult for us to imagine a world without printed matter. We find evidence of print everywhere around us – in books, journals, newspapers, prints of famous paintin
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HAND PRINTING TO MECHANICAL PRINTING The earliest kind of print technology was developed in China, Japan and Korea. This was a system of hand printing. From AD 594 onwards, books in China were prin
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Oxidation You have learnt about oxidation reactions in the first Chapter. Once we shall recall what we have learnt. If a substance gains oxygen during a reaction, it i
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Addition Reaction Unsaturated hydrocarbons add hydrogen in the presence of catalysts such as palladium or nickel to give saturated hydrocarbons. Catalysts are substances that cause a reaction to oc
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Substitution Reaction Saturated hydrocarbons are fairly unreactive and are inert in the presence of most reagents. However, in the presence of sunlight, chlorine is added to hydrocarbons in a very
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PRINT IN JAPAN Buddhist missionaries from China introduced hand-printing technology into Japan around AD 768-770. The oldest Japanese book, printed in AD 868, is the Buddhist Diamond Sutra, contain
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Introduction Many carbon compounds are invaluable to us. But here we shall study the properties of two commercially important compounds – ethanol and ethanoic acid. Properties
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WOODBLOCK PRINTING For centuries, silk and spices from China flowed into Europe through the silk route. In the eleventh century, Chinese paper reached Europe via the same route. Paper made possible
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GUTENBERG AND THE PRINTING PRESS Gutenberg was the son of a merchant and grew up on a large agricultural estate. From his childhood he had seen wine and olive presses. Subsequently, he learnt the a
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A NEW READING PUBLIC What was the print revolution? It was not just a development, a new way of producing books; it transformed the lives of people, changing their relationship to information and k
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RELIGIOUS DEBATES AND THE FEAR OF PRINT Print created the possibility of wide circulation of ideas, and introduced a new world of debate and discussion. Even those who disagreed with established au
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PRINT AND DISSENT Print and popular religious literature stimulated many distinctive individual interpretations of faith even among little-educated working people. In the sixteenth century, Menocch
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LITERACY AND LITERATURE Through the seventeenth and eighteenth centuries literacy rates went up in most parts of Europe. Churches of different denominations set up schools in villages, carrying lit
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‘TREMBLE, THEREFORE, TYRANTS OF THE WORLS!’ By the mid-eighteenth century, there was a common conviction that books were a means of spreading progress and enlightenment. Many believed t
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PRINT CULTUR AND FRENCH REVOLUTION Many historians have argued that print culture created the conditions within which French Revolution occurred. Can we make such a connection? Three types of ar
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CHILDREN, WOMEN AND WORKERS The nineteenth century saw vast leaps in mass literacy in Europe, bringing in large numbers of new readers among children, women and workers. As primary education bec
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FURTHER INNOVATIONS By the late eighteenth century, the press came to be made out of metal. Through the nineteenth century, there were a series of further innovations in printing technology. By the
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MANUSCRIPTS BEFORE THE AGE OF PRINT Let us see when printing began in India and how ideas and information were written before the age of print. India had a very rich and old tradition of handwri
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PRINT COMES TO INDIA The printing press first came to Goa with Portuguese missionaries in the mid-sixteenth century. Jesuit priests learnt Konkani and printed several tracts. By 1674, about 50 book
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Ethanoic acid Ethanoic acid is commonly called acetic acid and belongs to a group of acids called carboxylic acids. 5-8% solution of acetic acid in water is called vinegar and is used wid
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INTENSE DEBATES AROUND RELIGIOUS ISSUES From the early nineteenth century, as you know, there were intense debates around religious issues. Different groups confronted the changes happening within
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WHY NEWSPAPERS? Bombay Telegraph and Courier, 6 January 1849 'Krishnaji Trimbuck Ranade inhabitant of Poona intends to publish a Newspaper in the Marathi Language with a view of affording us
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PRINT AND VISUAL CULTURE Printing created an appetite for new kinds of writing. As more and more people could now read, they wanted to see their own lives, experiences, emotions and relationships r
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Reactions of ethanoic acid: Esterification reaction: Activity 4.8 Take 1 mL ethanol (absolute alcohol) and 1 mL glacial acetic acid along with a few drops of con
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Soap and its Cleaning Action Soap: On treating with sodium hydroxide, which is an alkali, the ester is converted back to alcohol and sodium salt of carboxylic acid. This reaction is kn
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Role of Soap and Detergent in Hard Water Activity 4.11 Take about 10 mL of distilled water (or rainwater) and 10 mL of hard water (from a tubewell or hand-pump) in separate t
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WOMEN AND PRINT Lives and feelings of women began to be written in particularly vivid and intense ways. Women’s reading, therefore, increased enormously in middle-class homes. Liberal husband
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PRINT AND THE POOR PEOPLE Very cheap small books were brought to markets in nineteenth-century Madras towns and sold at crossroads, allowing poor people travelling to markets to buy them. Public li
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PRINT AND CENSORSHIP Before 1798, the colonial state under the East India Company was not too concerned with censorship. Strangely, its early measures to control printed matter were directed agains
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Alive or Not Alive How do we tell the difference between what is alive and what is not alive? If we see a dog running, or a cow chewing cud, or a man shouting loudly on the street,
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What are Life Processes? The maintenance functions of living organisms must go on even when they are not doing anything particular. Even when we are just sitting in class, even if we
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Introduction When we walk or ride a bicycle, we are using up energy. Even when we are not doing any apparent activity, energy is needed to maintain a state of order in our body. We also n
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How do Organisms Obtain Their Food? Since the food and the way it is obtained differ, the digestive system is different in various organisms. In single-celled organisms, the food may be taken in by
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What is Autotrophic Nutrition? The general requirement for energy and materials is common in all organisms, but it is fulfilled in different ways. Some organisms use simple food material obtained f
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What is Photosynthesis? The carbon and energy requirements of the autotrophic organism are fulfilled by photosynthesis. It is the process by which autotrophs take in substances from the
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INTRODUCTION TO CHEMICAL REACTION AND EQUATION Consider the following situations of daily life and think what happens when * milk is left at room temperature during summers. * an i
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Bell Jar Experiment Activity 6.2 Take two healthy potted plants that are nearly the same size. Keep them in a dark room for three days. Now place each plant on separate
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Heterotrophic Nutrition Each organism is adapted to its environment. The form of nutrition differs depending on the type and availability of food material as well as how it is obtained by
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WRITING A CHEMICAL EQUATION Is there any other shorter way for representing chemical equations? Chemical equations can be made more concise and useful if we use chemical formulae instead of words.
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Role of Tongue, Mouth, and Oesophagus The alimentary canal is basically a long tube extending from the mouth to the anus. Figure 6.6 Human alimentary canal In Fig. 6.
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Role of Stomach and Intestine in Digestion The stomach is a large organ that expands when food enters it. The muscular walls of the stomach help in mixing the food
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BALANCING CHEMICAL EQUATIONS Recall the law of conservation of mass that you studied in Class IX; mass can neither be created nor destroyed in a chemical reaction. That is, the total mass of the el
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INTRODUCTION TO TYPES OF CHEMICAL REACTIONS We have learnt in Class IX that during a chemical reaction atom of one element do not change into those of another element. Nor do atoms disappear from t
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COMBINATION REACTION Activity 1.4: Figure 1.3: Formation of slaked lime by the reaction of calcium oxide with water * Take a small amount of calcium oxide or qui
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Respiration Activity 6.4 Take some freshly prepared lime water in a test tube. Blow air through this lime water. Note how long it takes for the lime water to turn milky
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Various Pathways of Respiration We have discussed nutrition in organisms in the last section. The food material taken in during the process of nutrition is used in cells to provide energy
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Adenosine Tri Phosphate (ATP) The energy released during cellular respiration is immediately used to synthesise a molecule called ATP which is used to fuel all other activities in the cell. In thes
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DECOMPOSTION REACTION Activity 1.5: Figure 1.4: Correct way of heating the boiling tube containing crystals of ferrous sulphate and of smelling the odour.
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Aerobic Respiration some organisms use oxygen to break-down glucose completely into carbon dioxide and water. The first step is the break-down of glucose, a six-carbon molecule, into a three-carbon
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Respiration in Human Beings In human beings (Fig. 6.9) The air is taken into the body through the nostrils. The air passing through the nostrils is filtered by fine
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DOUBLE DISPLACEMENT REACTION Activity 1.10 ( Double Displacement Reaction between Barium Chloride and Sodium Sulphate ): Figure 1.9: Formation of barium sulphate and sodium ch
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OXIDATION AND REDUCTION Activity 1.11: Figure 1.10: Oxidation of copper to copper oxide * Heat a china dish containing about 1 g copper powder (Fig. 1.10). *  
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CORROSION You must have observed that iron articles are shiny when new, but get coated with a reddish-brown powder when left for some time. This process is commonly known as rusting of iron. S
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RANCIDITY Have you ever tasted or smelt the fat/oil containing food materials left for a long time? When fats and oils are oxidised, they become rancid and their smell and taste change
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BLOOD – FLUID CONNECTIVE TISSUE Activity 6.7 * Visit a health centre in your locality and find out what is the normal range of haemoglobin content in human beings. * &nb
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OUR PUMP – THE HEART The heart is a muscular organ which is as big as our fist (Fig. 6.10). Because both oxygen and carbon dioxide have to be transported by the blood, the heart has different
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ENTRY OF OXYGEN TO BLOOD The separation of the right side and the left side of the heart is useful to keep oxygenated and deoxygenated blood from mixing. Such separation allows a highly efficient s
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THE TUBES – BLOOD VESSELS Arteries are the vessels which carry blood away from the heart to various organs of the body. Since the blood emerges from the heart under high pressure, the arterie
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LYMPH There is another type of fluid also involved in transportation. This is called lymph or tissue fluid. Through the pores present in the walls of capillaries some amount of plasma, proteins and
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TRANSPORTATION IN PLANTS We have discussed earlier how plants take in simple compounds such as CO2 and photosynthesise energy stored in their chlorophyll -containing organs, namely leaves. The othe
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TRANSPORT OF WATER In xylem tissue, vessels and tracheids of the roots, stems, and leaves are interconnected to form a continuous system of water-conducting channels reaching all parts of the plant
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TRANSPORT OF FOOD AND OTHER SUBSTANCES So far we have discussed the transport of water and minerals in plants. Now let us consider how the products of metabolic processes, particularly photosynthes
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WHAT IS EXCRETION? We have already discussed how organisms get rid of gaseous wastes generated during photosynthesis or respiration. Other metabolic activities generate nitrogenous materials which
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EXCRETION IN HUMAN BEINGS The excretory system of human beings (Fig. 6.13) includes a pair of kidneys, a pair of ureters, a urinary bladder and a urethra. Kidneys are located in the abdomen, one on
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MORE TO KNOW – ARTIFICIAL KIDNEY (HEMODIALYSIS) Kidneys are vital organs for survival. Several factors like infections, injury, or restricted blood flow to kidneys reduce the activity of kidn
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EXCRETION IN PLANTS Plants use completely different strategies for excretion than those of animals. Oxygen itself can be thought of as a waste product generated during photosynthesis! We have discu
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INTRODUCTION In the previous chapter, we looked at the life processes involved in the maintenance functions in living organisms. There, we had started with a notion we all have, that if we see s
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WHAT IS NERVOUS TISSUE? In animals, such control and coordination are provided by nervous and muscular tissues, which we have studied in Class IX. Touching a hot object is an urgent and d
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HOW NEURONS WORK? So far, we have been talking about nervous tissue, and how it collects information, sends it around the body, processes information, makes decisions based on information, and con
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WHAT HAPPENS IN REFLEX ACTIONS? ‘ Reflex ’ is a word we use very commonly when we talk about some sudden action in response to something in the environment. We say ‘I jumped out
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HUMAN BRAIN & SPINAL CORD Is reflex action the only function of the spinal cord? Obviously not, since we know that we are thinking beings. Spinal cord is made up of nerves which supply informa
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PROTECTION OF TISSUES A delicate organ like the brain, which is so important for a variety of activities, needs to be carefully protected. For this, the body is designed so that the brain sits insi
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PLANTS RESPONSE TO STIMULUS Coordination in Plants Animals have a nervous system for controlling and coordinating the activities of the body. But plants have neither a nervous system nor muscles
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MOVEMENT DUE TO GROWTH Some plants like the pea plant climb up other plants or fences by means of tendrils. These tendrils are sensitive to touch. When they come in contact with any support, the pa
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WHAT ARE HORMONES? How are such chemical, or hormonal, means of information transmission used in animals? What do some animals, for instance, squirrels, experience when they are in a scary sit
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ADRENALINE Adrenaline is secreted directly into the blood and carried to different parts of the body. The target organs or the specific tissues on which it acts include the heart. As a result, the
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THYROXIN Let us examine some examples to understand how hormones help in coordinated growth. We have all seen salt packets which say ‘iodised salt’ or ‘enriched with iodine’
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GROWTH HORMONE Sometimes we come across people who are either very short (dwarfs) or extremely tall (giants). Have you ever wondered how this happens? Growth hormone is one of the hormones secreted
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TESTOSTERONE AND OESTROGEN You must have noticed many dramatic changes in your appearance as well as that of your friends as you approached 10–12 years of age. These changes associated with p
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INSULIN Do you know anyone in your family or friends who has been advised by the doctor to take less sugar in their diet because they are suffering from diabetes? As a treatment, they might be taki
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FISSION Activity 8.1: * Dissolve about 10 gm of sugar in 100 mL of water. * Take 20 mL of this solution in a test tube and add a pinch of yeast granules to it. * 
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FRAGMENTATION Activity 8.4: * Collect water from a lake or pond that appears dark green and contains filamentous structures. * Put one or two filaments on a slide. *&
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REGENERATION Many fully differentiated organisms have the ability to give rise to new individual organisms from their body parts. That is, if the individual is somehow cut or broken up into many pi
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BUDDING Organisms such as Hydra use regenerative cells for reproduction in the process of budding. In Hydra, a bud develops as an outgrowth due to repeated cell division at one specific site (
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VEGETATIVE PROPAGATION There are many plants in which parts like the root, stem and leaves develop into new plants under appropriate conditions. Unlike in most animals, plants can indeed use such a
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SPORE FORMATION Even in many simple multi-cellular organisms, specific reproductive parts can be identified. The thread-like structures that developed on the bread in Activity 8.2 above are the hyp
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WHY THE SEXUAL MODE OF REPRODUCTION? We are also familiar with modes of reproduction that depend on the involvement of two individuals before a new generation can be created. Bulls alone cannot pro
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REPRODUCTIVE PARTS OF A FLOWER The reproductive parts of angiosperms are located in the flower. You have already studied the different parts of a flower – sepals, petals stamens and pist
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PROCESS OF FERTILIZATION The ovary contains ovules and each ovule has an egg cell. The male germ-cell produced by pollen grain fuses with the female gamete present in the ovule. This fusion of
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INTRODUCTION So far, we have been discussing the variety of modes that different species use for reproduction. Let us now look at the species that we are most interested in, namely, humans. Humans
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MALE REPRODUCTIVE SYSTEM The male reproductive system (Fig. 8.10) consists of portions which produce the germ-cells and other portions that deliver the germ-cells to the site of fertilisation. &
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FEMALE REPRODUCTIVE SYSTEM The female germ-cells or eggs are made in the ovaries. They are also responsible for the production of some hormones. Look at Fig. 8.11 and identify the various organs in
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WHAT HAPPENS WHEN THE EGG IS NOT FERTILIZED? If the egg is not fertilised, it lives for about one day. Since the ovary releases one egg every month, the uterus also prepares itself every month to r
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REPRODUCTIVE HEALTH As we have seen, the process of sexual maturation is gradual and takes place while general body growth is still going on. Therefore, some degree of sexual maturation does n
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INTRODUCTION Before we discuss the mechanisms by which organisms reproduce, let us ask a more basic question – why do organisms reproduce? After all, reproduction is not necessary to maintain
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ORGANISMS LOOK SIMILAR? Organisms look similar because their body designs are similar. If body designs are to be similar, the blueprints for these designs should be similar. Thus, reproduction at i
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THE STABILITY OF POPULATIONS OF SPECIES Populations of organisms fill well-defined places, or niches, in the ecosystem, using their ability to reproduce. The consistency of DNA copying during repro
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INTRODUCTION We have seen that reproductive processes give rise to new individuals that are similar, but subtly different. We have discussed how some amount of variation is produced even durin
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INHERITED TRAITS What exactly do we mean by similarities and differences? We know that a child bears all the basic features of a human being. However, it does not look exactly like its parents, and
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MENDEL’S CONTRIBUTIONS The rules for inheritance of such traits in human beings are related to the fact that both the father and the mother contribute practically equal amounts of genetic mat
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EXPRESSION OF TRAITS How does the mechanism of heredity work? Cellular DNA is the information source for making proteins in the cell. A section of DNA that provides information for one protein is c
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SEX DETERMINATION We have discussed the idea that the two sexes participating in sexual reproduction must be somewhat different from each other for a number of reasons. How is the sex of a newborn
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AN ILLUSTRATION We have noted that there is an inbuilt tendency to variation during reproduction, both because of errors in DNA copying, and as a result of sexual reproduction. Let us now look at s
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ACQUIRED AND INHERITED TRAITS We discussed the idea that the germ cells of sexually reproducing populations are made in specialised reproductive tissue. If the weight of the beetle is reduced becau
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SPECIATION What we have seen so far is micro-evolution. That means that the changes are small, even though they are significant. Also, they simply change the common characteristics of a particular
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IDENTIFYING HIERARCHIES Based on these principles, we can work out the evolutionary relationships of the species we see around us. It is a sort of going backwards in time. We can do this by identif
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TRACING EVOLUTIONARY RELATIONSHIPS When we try to follow evolutionary relationships, how do we identify characteristics as common? These characteristics in different organisms would be similar beca
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FOSSILS Such studies of organ structure can be done not only on current species, but also on species that are no longer alive. How do we know that these extinct species ever existed? We know this f
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EVOLUTION BY STAGES A question that arises here is – if complicated organs, such as the eye, are selected for the advantage they provide, how can they be generated by a single DNA change? Sur
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EVOLUTION NOT EQUATED WITH PROGRESS In an exercise of tracing the family trees of species, we need to remember certain things. Firstly, there are multiple branches possible at each and every
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THE HUMAN EVOLUTION The same tools for tracing evolutionary relationships – excavating, time-dating, and studying fossils, as well as determining DNA sequences – have bee
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ECOSYSTEM AND ITS COMPONENTS We have heard the word ‘environment’ often being used on the television, in newspapers and by people around us. Our elders tell us that the &lsquo
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FOOD CHAINS AND WEBS In Figure 15.4 we have formed a series of organisms feeding on one another. This series or organisms taking part at various biotic levels form a food chain (Fig. 15.1).
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FOOD CHAINS AND WEBS We are an integral part of the environment. Changes in the environment affect us and our activities change the environment around us. We have already seen in Class IX how
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MANAGING THE GARBAGE WE PRODUCE In our daily activities, we generate a lot of material that are thrown away. What are some of these waste materials? What happens after we throw them away? Let
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INTRODUCTION ‘Living in harmony with nature’ is not new to us. Sustainable living has always been an integral part of India’s tradition and culture. It has been integrated with ou
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R 5 PRINCIPLE We need not feel powerless or overwhelmed by the scale of the problems because there are many things we can do to make a difference. You must have come across the five R’s to sa
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WHY TO MANAGE RESOURCES? Not just roads and buildings, but all the things we use or consume – food, clothes, books, toys, furniture, tools and vehicles – are obtained from resources on
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STAKEHOLDERS Activity 16.6: * Make a list of forest produce that you use. * What do you think a person living near a forest would use? * What do you think
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MANAGEMENT OF FOREST We need to consider if the goals of all the above stakeholders with regard to the management of the forests are the same. Forest resources are often made available for industri
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WATER – A BASIC NECESSITY Activity 16.9: * Villages suffering from chronic water shortage surround a water theme park in Maharashtra. Debate whether this is the optimum use of
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DAMS Why do we seek to build dams? Large dams can ensure the storage of adequate water not just for irrigation, but also for generating electricity, as discussed in the previous chapter. Canal system
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WATER HARVESTING Watershed management emphasises scientific soil and water conservation in order to increase the biomass production. The aim is to develop primary resources of land and water, to prod
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COAL AND PETROLEUM We have seen some of the issues involved in the conservation and sustainable use of resources like forests, wildlife and water. These can meet our needs perpetually if we were to u
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OUR RESPONSIBILITY Sustainable management of natural resources is a difficult task. In addressing this issue, we need to keep an open mind with regard to the interests of various stakeholders. We n
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INTRODUCTION AND CLASSIFICATION OF RESOURCES Everything available in our environment which can be used to satisfy our needs, provided, it is technologically accessible, economically feasible and cu
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ON BASIS OF ORIGIN AND EXHAUSTIBILITY Renewable Resources: The resources which can be renewed or reproduced by physical, chemical or mechanical processes are known as renewable or replenishable
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ON BASIS OF OWNERSHIP Individual Resources: These are also owned privately by individuals. Many farmers own land which is allotted to them by the government against the payment of revenue. In v
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ON THE BASIS OF THE STATUS OF DEVELOPMENT Potential Resources: Resources which are found in a region, but have not been utilised. For example, the western parts of India particularly Rajasthan
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SUSTAINABLE RESOURCES Sustainable development: Sustainable economic development means ‘development should take place without damaging the environment, and development in the present shoul
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RESOURCES PLANNING Planning is the widely accepted strategy for judicious use of resources. It has importance in a country like India, which has enormous diversity in the availability of resources.
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RESOURCES PLANNING IN INDIA Resource planning is a complex process which involves : (i) identification and inventory of resources across the regions of the country. This involves surveying, mapp
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LAND RESOURCES We live on land, we perform our economic activities on land and we use it in different ways. Thus, land is a natural resource of the utmost importance. It supports natural veget
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LAND UTILIZATION Land resources are used for the following purposes: 1. Forests 2. Land not available for cultivation (a) Barren and wasteland
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LAND USE PATTERN IN INDIA The use of land is determined both by physical factors such as topography, climate, soil types as well as human factors such as population density, technological capabilit
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LAND DEGRADATION AND CONSERVATION MEASURES We have shared our land with the past generations and will have to do so with the future generations too. Ninety-five percent of our basic needs for
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We see a variety of objects in the world around us. However, we are unable to see anything in a dark room. On lighting up the room, things become visible. What makes things visible? During the day, su
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Reflection of Light A highly polished surface, such as a mirror, reflects most of the light falling on it. You are already familiar with the laws of reflection of light Let us recall these laws
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Concave and Convex Mirror Concave and Convex Mirror The reflecting surface of a spherical mirror may be curved inwards or outwards. A spherical mirror, whose reflecting surface is curved inwards, t
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Image Formation by Spherical Mirrors You have studied the image formation by plane mirrors. You also know the nature, position, and relative size of the images formed by them. How about the images
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Representation of Images Formed by Spherical Mirrors Using Ray Diagrams We can also study the formation of images by spherical mirrors by drawing ray diagrams. Consider an extended
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Image formation by Concave Mirror Figure 10.7 illustrates the ray diagrams for the formation of the image by a concave mirror for various positions of the object. Figure 10.7 Ray diagrams fo
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Image formation by Convex Mirror We studied the image formation by a concave mirror. Now we shall study the formation of image by a convex mirror. Activity 10.5 Take a convex mirror. Hold it
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SOIL AS A RESOURCES Soil is the most important renewable natural resource. It is the medium of plant growth and supports different types of living organisms on the earth. The soil is a living syste
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ALLUVIAL, BLACK, RED AND YELLOW SOILS Alluvial Soils This is the most widely spread and important soil. In fact, the entire northern plains are made of alluvial soil. These have been deposited b
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LATERITE, ARID AND FOREST SOILS Laterite Soils Laterite has been derived from the Latin word ‘later’ which means brick. The laterite soil develops under tropical and subtropical
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SOIL EROSION AND CONSERVATION The denudation of the soil cover and subsequent washing down is described as soil erosion. The processes of soil formation and erosion, go on simultaneously and genera
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INTRODUCTION * Lepcha folk song from the northern part of West Bengal Narak! My Lord, you are the creator of music in the world of Lepchas. Oh Narak! My Lord, let me dedicate myself to y
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FLORA AND FAUNA IN INDIA If you look around, you will be able to find that there are some animals and plants which are unique in your area. In fact, India is one of the world’s richest countr
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SPECIES CLASSIFICATION ON LEVEL OF SURVIVAL Let us now understand the different categories of existing plants and animal species. Based on the International Union for Conservation of Nature and Nat
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DEFORESTATION AND MINING Vanishing Forest The dimensions of deforestation in India are staggering. The forest and tree cover in the country is estimated at 79.42 million hectare, which is 24.16
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OTHER ENVIRONMENTAL DESTRUCTION Other important causes of environmental destruction are unequal access, inequitable consumption of resources and differential sharing of responsibility for environme
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Sign Convention for Spherical Lenses For lenses, we follow sign convention, similar to the one used for spherical mirrors. We apply the rules for signs of distances, except that all measu
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LOSS OF CULTURAL DIVERSITY The destruction of forests and wildlife is not just a biological issue. The biological loss is strongly correlated with the loss of cultural diversity. Such losses have i
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Power of a Lens You have already learnt that the ability of a lens to converge or diverge light rays depends on its focal length. For example, a convex lens of short focal length bends the light ra
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TYPES AND DISTRIBUTION OF FOREST AND WILDLIFE RESOURCES Even if we want to conserve our vast forest and wildlife resources, it is rather difficult to manage, control and regulate them. In India, mu
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CONSERVE OUR FOREST AND WILDLIFE Conservation in the background of the rapid decline in wildlife population and forestry has become essential. But why do we need to conserve our forests and wi
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COMMUNITY AND CONSERVATION Conservation in the background of the rapid decline in wildlife population and forestry has become essential. But why do we need to conserve our forests and wildlife
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Introduction You have studied in the previous chapter about refraction of light by lenses. You also studied the nature, position and relative size of images formed by lenses. How can these ideas he
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Power of Accommodation The eye lens is composed of fibrous, jelly-like material. Its curvature can be modified to some extent by the ciliary muscles. The change in the curvature of the eye lens can
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WATER SCARCITY Introduction You already know that three-fourths of the earth’s surface is covered with water, but only a small proportion of it accounts for freshwater that can be put
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Common refractive defects of vision Sometimes, the eye may gradually lose its power of accommodation. In such conditions, the person cannot see the objects distinctly and comfortably. The vision be
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HOW DO WE CONSERVE AND MANAGE WATER? But, how do we conserve and manage water? Archaeological and historical records show that from ancient times we have been constructing sophisticated hydraulic s
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Refraction Of Light Through A Prism You have learnt how the light gets refracted through a rectangular glass slab. For parallel refracting surfaces, as in a glass slab, the emergent ray is parallel
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DAMS - TEMPLES OF MODERN INDIA What are dams and how do they help us in conserving and managing water? A dam is a barrier across flowing water that obstructs, directs, or retards the
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SCRUTINY AND OPPOSITION In recent years, multi-purpose projects and large dams have come under great scrutiny and opposition for a variety of reasons. Regulating and damming of rivers affect their
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ROLE OF IRRIGATION Irrigation has also changed the cropping pattern of many regions with farmers shifting to water-intensive and commercial crops. This has great ecological consequences like salini
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Dispersion of White Light By A Glass Prism You must have seen and appreciated the spectacular colours in a rainbow. How could the white light of the Sun give us various colours of the rainbow? Befo
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WATER HARVESTING SYSTEM - AVAILABLE ALTERNATIVE Many thought that given the disadvantages and rising resistance against the multi-purpose projects, a water harvesting system w
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TANKAS In the semi-arid and arid regions of Rajasthan, particularly in Bikaner, Phalodi and Barmer, almost all the houses traditionally had underground tanks or tankas for storing drinking water.
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Atmospheric Refraction You might have observed the apparent random wavering or flickering of objects seen through a turbulent stream of hot air rising above a fire or a radiator. The air
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Scattering Of Light The interplay of light with objects around us gives rise to several spectacular phenomena in nature. The blue colour of the sky, colour of water in the deep sea, the reddening o
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Why is the colour of the clear Sky Blue? The molecules of air and other fine particles in the atmosphere have a size smaller than the wavelength of visible light. These are more effective
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BAMBOO DRIP IRRIGATION SYSTEM In Meghalaya, a 200-year-old system of tapping stream and spring water by using bamboo pipes, is prevalent. About 18-20 litres of water enters the bamboo pipe system,
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Colour of the Sun at Sunrise and Sunset Have you seen the sky and the Sun at sunset or sunrise? Have you wondered as to why the Sun and the surrounding sky appear red? Let us do an activi
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PRIMITIVE SUBSISTENCE FARMING Introduction India is an agriculturally important country. Two-thirds of its population is engaged in agricultural activities. Agriculture is a primary activity, wh
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INTENSIVE SUBSISTENCE FARMING This type of farming is practised in areas of high population pressure on land. It is labour- intensive farming, where high doses of biochemical inputs and irrigation
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COMMERCIAL FARMING The main characteristic of this type of farming is the use of higher doses of modern inputs, e.g. high yielding variety (HYV) seeds, chemical fertilisers, insecticides and p
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RABI, KHARIF AND ZAID You have studied the physical diversities and plurality of cultures in India. These are also reflected in agricultural practices and cropping patterns in the country. Various
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RICE, WHEAT AND PULSES A variety of food and non-food crops are grown in different parts of the country depending upon the variations in soil, climate and cultivation practices. Major crops grown i
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MILLETS AND MAIZE Millets Jowar, bajra and ragi are the important millets grown in India. Though these are known as coarse grains, they have very high nutritional value. For example, ragi is ver
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SUGARCANE It is a tropical as well as a subtropical crop. It grows well in a hot and humid climate with a temperature of 21°C to 27°C and annual rainfall between 75cm. and 100cm. Irrigation
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OILSEEDS In 2016 India was the second-largest producer of groundnut in the world after China. In rapeseed production, India was the third-largest producer in the world after Canada and China in 201
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TEA AND COFFEE Tea Tea cultivation is an example of plantation agriculture. It is also an important beverage crop introduced in India initially by the British. Today, most of the tea plantations
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HORTICULTURE CROPS In 2016, India was the second largest producer of fruits and vegetables in the world after China. India is a producer of tropical as well as temperate fruits. Mangoes of Maharash
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RUBBER It is an equatorial crop, but under special conditions, it is also grown in tropical and sub-tropical areas. It requires moist and humid climate with rainfall of more than 200 cm. and temper
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FIBRE CROPS - COTTON AND JUTE Fibre crops Cotton, jute, hemp and natural silk are the four major fibre crops grown in India. The first three are derived from the crops grown in the so
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TECHNO – INSTITUTIONAL CHANGES It was mentioned in the previous pages that agriculture has been practised in India for thousands of years. Sustained uses of land without compatible
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BHOODAN-GRAMDAN Mahatma Gandhi declared Vinoba Bhave as his spiritual heir. He also participated in Satyagraha as one of the foremost satyagrahis. He was one of the votaries of Gandh
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AGRICULTURAL SHARE IN THE GROSS DOMESTIC PRODUCT(GDP) Agriculture has been the backbone of the Indian economy through its share in the Gross Domestic Product (GDP) has registered a declin
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EFFECT OF GLOBALISATION OF FARMERS Globalisation is not a new phenomenon. It was there at the time of colonisation. In the nineteenth century when European traders came to India, at that time too,
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ORGANIC FARMING In fact, organic farming is much in vogue today because it is practised without factory-made chemicals such as fertilizers and pesticides. Hence, it does not affect the environment
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WHERE DO THESE METALS COME FROM? Introduction Haban comes to Guwahati with his father from a remote village. He sees people getting into a strange house like objects which move along t
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WHAT IS A MINERAL? Geologists define a mineral as a “homogenous, naturally occurring substance with a definable internal structure.” Minerals are found in varied forms in nature, rangin
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WHERE ARE THESE MINERALS FOUND? Minerals are usually found in “ores”. The term ore is used to describe an accumulation of any mineral mixed with other elements. The mineral content of t
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FERROUS MINERALS – IRON ORE, MANGANESE Ferrous minerals account for about three-fourths of the total value of the production of metallic minerals. They provide a strong base for the deve
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NON-FERROUS MINERALS – COPPER, BAUXITE Indias’ reserves and production of non- ferrous minerals are not very satisfactory. However, these minerals, which include copper, baux
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NONMETALLIC MINERALS – MICA Mica Mica is a mineral made up of a series of plates or leaves. It splits easily into thin sheets. These sheets can be so thin that a thousand can be layered in
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ROCK MINERALS – LIMESTONE Limestone Limestone is found in association with rocks composed of calcium carbonates or calcium and magnesium carbonates. It is found in sedimentary rocks of mos
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HAZARDS OF MINING Have you ever wondered about the efforts the miners make in making life comfortable for you? What are the impacts of mining on the health of the miners and the environment? T
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CONSERVATION OF MINERALS We all appreciate the strong dependence of industry and agriculture upon mineral deposits and the substances manufactured from them. The total volume of workable mineral de
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ENERGY RESOURCES Energy is required for all activities. It is needed to cook, to provide light and heat, to propel vehicles and to drive machinery in industries. Energy can be generated from fuel m
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COAL In India, coal is the most abundantly available fossil fuel. It provides a substantial part of the nation’s energy needs. It is used for power generation, to supply energy to the in
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PETROLEUM AND NATURAL GAS Petroleum Petroleum or mineral oil is the next major energy source in India after coal. It provides fuel for heat and lighting, lubricants for machinery, and raw materi
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ELECTRICITY Electricity has such a wide range of applications in today's world that, its per capita consumption is considered as an index of development. Electricity is gene
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NUCLEAR OR ATOMIC ENERGY, SOLAR ENERGY Non-Conventional Sources of Energy The growing consumption of energy has resulted in the country becoming increasingly dependent on fossil fuels such as co
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WINDPOWER, BIOGAS Windpower India has great potential of wind power. The largest wind farm cluster is located in Tamil Nadu from Nagarcoil to Madurai. Apart from these, Andhra Pradesh,
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TIDAL ENERGY, GEOTHERMAL ENERGY Tidal energy Oceanic tides can be used to generate electricity. Floodgate dams are built across inlets. During high tide, water flows into the inlet and
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ENERGY SAVED IS ENERGY PRODUCED Energy is a basic requirement for economic development. Every sector of the national economy – agriculture, industry, transport, commercial, and domestic &ndas
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SOME IDEAS ABOUT INDUSTRIES On the occassion of Diwali, Harish went to a market with his parents. They purchased shoes and clothes for him. His mother purchased utensils, sugar, tea and diyas (eart
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BACKBONE OF DEVELOPMENT Manufacturing sector is considered the backbone of development in general and economic development in particular mainly because - * Manufacturing industries n
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CONTRIBUTION TO NATIONAL ECONOMY Over the last two decades, the share of the manufacturing sector has stagnated at 17 percent of GDP – out of a total of 27 percent for the industry
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INDUSTRIAL LOCATION Industrial locations are complex in nature. These are influenced by the availability of raw material, labour, capital, power and market, etc. It is rarely possible to find
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ON THE BASIS OF SOURCE OF RAW MATERIALS Classification of Industries List the various manufactured products you use in your daily life such as – transistors, electric bulbs, vegetable oil,
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ON THE BASIS OF OWNERSHIP * Public sector, owned and operated by government agencies – BHEL, SAIL etc. * Private sector industries owned and operated by individuals
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BASED ON BULK AND WEIGHT Based on the bulk and weight of raw material and finished goods: * Heavy industries such as iron and steel * Light industries that use light r
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TEXTILES INDUSTRY – COTTON TEXTILES Agro-based Industries Cotton, jute, silk, woollen textiles, sugar and edible oil, etc. industries are based on agricultural raw materials.
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JUTE TEXTILES India is the largest producer of raw jute and jute goods and stands at second place as an exporter after Bangladesh. Most of the mills are located in West Bengal, mainly alo
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SUGAR INDUSTRY India stands second as a world producer of sugar but occupies first place in the production of gur and khandsari. The raw material used in this industry is bulky, and in haulage its
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IRON AND STEEL INDUSTRY Mineral-based Industries Industries that use minerals and metals as raw materials are called mineral-based industries. Can you name some industries that would fall in thi
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ALUMINIUM SMELTING Aluminium smelting is the second most important metallurgical industry in India. It is light, resistant to corrosion, a good conductor of heat, malleable and becomes strong when
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FAST GROWING AND DIVERSIFYING The Chemical industry in India is fast growing and diversifying. It comprises both large and small scale manufacturing units. Rapid growth has been recorded in both in
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FERTILIZER AND CEMENT INDUSTRY Fertilizer Industry The fertilizer industry is centred around the production of nitrogenous fertilizers (mainly urea), phosphatic fertilizers and ammonium phosphat
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FERTILIZER AND CEMENT INDUSTRY Automobile Industry Automobiles provide vehicle for quick transport of good services and passengers. Trucks, buses, cars, motor cycles, scooters, three-wheelers an
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AIR AND WATER POLLUTION Industrial Pollution and Environmental Degradation Although industries contribute significantly to India’s economic growth and development, the increase in pollutio
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THERMAL AND NOISE POLLUTION Thermal pollution Thermal pollution of water occurs when hot water from factories and thermal plants is drained into rivers and ponds before cooling. What would be th
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CONTROL OF INDUSTRIAL POLLUTION Every litre of waste water discharged by our industry pollutes eight times the quantity of freshwater. How can the industrial pollution of fresh water be reduce
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DISPLACEMENT REACTION Activity 1.9 ( Iron displacing copper from copper sulphate solution ): Figure 1.8(a): Iron nails dipped in copper sulphate solution * &
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Before you read They say faith can move mountains. But what should we put our faith in? This is the question this story delicately poses. Lencho is a farmer who writes a letter to God
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DUST OF SNOW - ROBERT FROST (Poet) Poem The way a crow Shook down on me The dust of snow From a hemlock tree Has given my heart A change of mood And saved some p
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FIRE AND ICE - ROBERT FROST (Poet) Poem Some say the world will end in fire Some say in ice. From what I’ve tasted of desire I hold with those who favour fire But i
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Before you read * ‘Apartheid’ is a political system that separates people according to their race. Can you say which of the three countries named below had such a poli
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A TIGER IN THE ZOO - LESLIE NORRIS (Poet) Poem He stalks in his vivid stripes The few steps of his cage, On pads of velvet quiet, In his quiet rage. He should be lurking i
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Before you read Since the earliest times, humans have dreamt of conquering the skies. Here are two stories about flying. I. A young seagull is afraid to fly. How does he conquer his
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STORY – BLACK AEROPLANE – FREDERICK FORSYTH (Author) The moon was coming up in the east, behind me, and stars were shining in the clear sky above me. There wasn’t a cloud in the s
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How to Tell Wild Animals - CAROLYN WELLS (Poet) Poem If ever you should go by chance To jungles in the east; And if there should to you advance A large and tawny beast, If he roars
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THE BALL POEM - JOHN BERRYMAN (Poet) Before you read A boy loses a ball. He is very upset. A ball doesn’t cost much, nor is it difficult to buy another ball. Why then is the boy so upset?
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Before you read Anneliese Marie ‘Anne’ Frank (12 June 1929 – February/March 1945) was a German-born Jewish girl who wrote while in hiding with her family and four friends i
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Amanda! - ROBIN KLEIN (Poet) Poem Don’t bite your nails, Amanda! Don’t hunch your shoulders, Amanda! Stop that slouching and sit up straight, Amanda! (There is a
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Before you read * How do we judge the people around us — by their money, wealth and possessions? Or is there something of more enduring value to look for in a person? * &
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STORY – THE HUNDRED DRESSES - II – ELEANOR ESTES (Author) While the class was circling the room, the monitor from the principal’s office brought Miss Mason a note. Miss Mason read
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ANIMALS - WALT WHITMAN (Poet) Before you read The poet tells us that he feels more at home with animals than humans, whom he finds complicated and false. The poem is taken from ‘So
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Before you read Activity: Discuss in class 1. What images — of people and of places — come to your mind, when you think of our country? 2. What parts of India have
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STORY – COORG – LOKESH ABROL (Author) Coorg is a coffee country, famous for its rainforests and spices. Midway between Mysore and the coastal town of Mangalore sits a piece
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STORY – TEA FROM ASSAM – ARUP KUMAR DATTA (Author) Pranjol, a youngster from Assam, is Rajvir’s classmate at school in Delhi. Pranjol’s father is the manager of a tea-garden
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THE TREES - ADRIENNE RICH (Poet) Before you read Can there be a forest without trees? Where are the trees in this poem, and where do they go? Poet Adrienne Rich was born in Balti
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Before you read Gavin Maxwell lives in a cottage in Camusfearna, in the West Highlands in Scotland. When his dog Jonnie died, Maxwell was too sad to think of keeping a dog again. But life
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FOG - CARL SANDBURG (Poet) Poem The fog comes on little cat feet. It sits looking over harbour and city on silent haunches and then moves on. &
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Before you read In this sensitive story, an eight-year-old girl’s first bus journey into the world outside her village is also her induction into the mystery of life and death. She sees the g
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THE TALE OF CUSTARD THE DRAGON – OGDEN NASH (Poet) Before you read This poem is written in the style of a ballad — a song or poem that tells a story. You must be familiar with bal
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Before you read [Source: Betty Renshaw Values and Voices: A College Reader (1975)] Activity: Use a dictionary or ask for your teacher’s help as you discuss the following qu
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FOR ANNE GREGORY - WILLIAM BUTLER YEATS (Poet) Before you read This poem is a conversation between a young man and a young woman. What are they arguing about? Poet William Butler
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Before you read ‘The Proposal’ (originally titled ‘A Marriage Proposal’) is a one-act play, a farce, by the Russian short-story writer and dramatist Anto
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TRANSPORT AND COMMUNICATION We use different materials and services in our daily life. Some of these are available in our immediate surroundings, while other requirements are met by bringing things
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ROADWAYS India has one of the largest road networks in the world, aggregating to about 56 lakh km. In India, roadways have preceded railways. They still have an edge over railways in view of the ea
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RAILWAYS Railways are the principal mode of transportation for freight and passengers in India. Railways also make it possible for people to conduct multifarious activities like business, sightseei
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PIPELINES Pipeline transport network is a new arrival on the transportation map of India. In the past, these were used to transport water to cities and industries. Now, these are used for transport
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WATERWAYS Since the ancient period, India was one of the seafaring countries. Its seamen sailed far and near, thus, carrying and spreading Indian commerce and culture. Waterways are the cheapest me
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AIRWAYS Air travel, today, is the fastest, most comfortable and prestigious mode of transport. It can cover very difficult terrains like high mountains, dreary deserts, dense forests and also
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DIFFERENT COMMUNICATION SYSTEMS Ever since humans appeared on the earth, they have used different means of communication. But, the pace of change, has been rapid in modern times. Long-distance comm
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INTERNATIONAL TRADE The exchange of goods among people, states, and countries is referred to as trade. The market is the place where such exchanges take place. Trade between the two countries is ca
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TOURISM AS A TRADE Tourism in India has grown substantially over the last three decades. More than 15 million people are directly engaged in the tourism industry. Tourism also promotes national
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WHAT IS DEVELOPMENT? The idea of development or progress has always been with us. We have aspirations or desires about what we would like to do and how we would like to live. Similarly, we have ide
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DIFFERENT PEOPLE AND DIFFERENT GOALS Let us try to imagine what development or progress is likely to mean to different persons listed in Table 1.1. What are their aspirations? You will find th
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INCOME AND OTHER GOALS Category of Person Developmental Goals/ Aspirations Landless rural labourers More days of work and better wages; local school is able to provi
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NATIONAL DEVELOPMENT If, as we have seen above, individuals seek different goals, then their notion of national development is also likely to be different. Discuss among yourselves on what India sh
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HOW TO COMPARE DIFFERENT COUNTRIES AND STATES? You might ask if development can mean different things, how come some countries are generally called developed and others underdeveloped? Before we co
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AVERAGE INCOME While ‘averages’ are useful for comparison, they also hide disparities. For example, let us consider two countries, A and B. For the sake of simplicity, we have a
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INCOME AND OTHER CRITERIA When we looked at individual aspirations and goals, we found that people not only think of better income but also have goals such as security, respect for others, equal tr
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PUBLIC FACILITIES How is it that the average person in Haryana has more income than the average person in Kerala but lags behind in these crucial areas? The reason is — money in your pocket c
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HUMAN DEVELOPMENT REPORT Once it is realised that even though the level of income is important, yet it is an inadequate measure of the level of development, we begin to think of other criteria. The
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GROUNDWATER AND EXHAUSTION OF NATURAL RESOURCES Sustainability of development Suppose for the present that a particular country is quite developed. We would certainly like this level of developm
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UNDERSTANDING SECTORS OF INDIAN ECONOMY An economy is best understood when we study its components or sectors. Sectoral classification can be done on the basis of several criteria. In this chapter,
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PRIMARY SECTORS Sectors Let us look at these pictures. You will find that people are engaged in various economic activities. Some of these are activities for producing goods. Some others are pro
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SECONDARY SECTOR The secondary sector covers activities in which natural products are changed into other forms through ways of manufacturing that we associate with industrial activity. It is the ne
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TERTIARY SECTOR After primary and secondary, there is a third category of activities that falls under tertiary sector and is different from the above two. These are activities that help in the deve
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COMPARING THREE SECTORS The various production activities in the primary, secondary and tertiary sectors produce a very large number of goods and services. Also, the three sectors have a large numb
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HISTORICAL CHANGE IN SECTORS Generally, it has been noted from the histories of many, now developed, countries that at initial stages of development, the primary sector was the most important secto
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RISING IMPORTANCE OF TERTIARY SECTOR IN PRODUCTION Primary, secondary and tertiary sectors in India Graph 1 shows the production of goods and services in the three sectors. This is shown for two
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WHERE ARE MOST OF THE PEOPLE EMPLOYED? Graph 2 presents percentage share of the three sectors in GDP. Now you can directly see the changing importance of the sectors over the forty years. &nbs
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HOW TO CREATE MORE EMPLOYMENT? From the previous discussion, we can see that there continues to be considerable underemployment in agriculture. There are also people who are not employed
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ORGANISED AND UNORGANISED SECTORS Let us examine another way of classifying activities in the economy. This looks at the way people are employed. What are their conditions of work? Are there any ru
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HOW TO PROTECT WORKERS IN THE UNORGANISED SECTORS? The organised sector offers jobs that are the most sought-after. But the employment opportunities in the organised sector have been expanding very
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PUBLIC AND PRIVATE SECTORS Another way of classifying economic activities into sectors could be on the basis of who owns assets and is responsible for the delivery of services. In the public se
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MONEY – APART OF LIFE Money is a fascinating subject and full of curiosities. It is important to capture this element for the students. The history of money and how various forms were used at
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DOUBLE COINCIDENCE OF WANTS The use of money spans a very large part of our everyday life. Look around you and you would easily be able to identify several transactions involving money in any singl
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CURRENCY We have seen that money is something that can act as a medium of exchange in transactions. Before the introduction of coins, a variety of objects was used as money. For example, since the
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DEPOSITS WITH BANKS The other form in which people hold money is as deposits with banks. At a point of time, people need only some currency for their day-to-day needs. For instance, workers who rec
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DEPOSITORS AND BORROWERS Let us take the story of banks further. What do the banks do with the deposits which they accept from the public? There is an interesting mechanism at work here. Banks keep
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FESTIVAL SEASON Two Different Credit Situations A large number of transactions in our day-to-day activities involve credit in some form or the other. Credit (loan) refers to an agreement in whic
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SWAPNA’S PROBLEM Swapna, a small farmer, grows groundnut on her three acres of land. She takes a loan from the moneylender to meet the expenses of cultivation, hoping that her harvest would h
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A HOUSE LOAN Terms of Credit Every loan agreement specifies an interest rate which the borrower must pay to the lender along with the repayment of the principal. In addition, lenders may de
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VARIETY OF CREDIT ARRANGEMENTS Example of a Village Rohit and Ranjan had finished reading about the terms of credit in the class. They were eager to know the various credit arrangements that exi
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LOANS FROM COOPERATIVES Besides banks, the other major source of cheap credit in rural areas are the cooperative societies (or cooperatives). Members of a cooperative pool their resources for
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FORMAL AND INFORMAL SECTOR LOANS We have seen in the above examples that people obtain loans from various sources. The various types of loans can be conveniently grouped as formal sector loans and
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FORMAL AND INFORMAL CREDIT: WHO GETS WHAT? Graph 2 shows the importance of formal and informal sources of credit for people in urban areas. The people are divided into four groups, from poor to ric
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SHGs In the previous section, we have seen that poor households are still dependent on informal sources of credit. Why is it so? Banks are not present everywhere in rural India. Even when they are
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GRAMEEN BANK OF BANGLADESH Grameen Bank of Bangladesh is one of the biggest success stories in reaching the poor to meet their credit needs at reasonable rates. Started in the 1970s as a small proj
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INTRODUCTION Most regions of the world are getting increasingly interconnected. While this interconnectedness across countries has many dimensions — cultural, political, social and economic &
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MULTINATIONAL CORPORATIONS Until the middle of the twentieth century, production was largely organised within countries. What crossed the boundaries of these countries were raw material, foods
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PRODUCTION BY MNCs In general, MNCs set up production where it is close to the markets; where there is skilled and unskilled labour available at low costs; and where the availability of other facto
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FOREIGN TRADE - THE MAIN CHANNEL For a long time, foreign trade has been the main channel connecting countries. In history, you would have read about the trade routes connecting India an
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WHAT IS GLOBALISATION? In the past two to three decades, more and more MNCs have been looking for locations around the world which would be cheap for their production. Foreign investment by MNCs in
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TECHNOLOGY Rapid improvement in technology has been one major factor that has stimulated the globalisation process. For instance, the past fifty years have seen several improvements in transportati
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LIBERALISATION OF POLICIES Let us return to the example of imports of Chinese toys in India. Suppose the Indian government puts a tax on the import of toys. What would happen? Those who wish t
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WTO – CONNECTIVITY OF TRADE We have seen that the liberalisation of foreign trade and investment in India was supported by some very powerful international organisations. These organisations
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IMPACT OF MNCS AND TOP INDIAN COMPANIES In the last twenty years, globalisation of the Indian economy has come a long way. What has been its effect on the lives of people? Let us look at some of th
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SMALL PRODUCERS – COMPETE OR PERISH For a large number of small producers and workers, globalisation has posed major challenges. Batteries, capacitors, plastics, toys, tyres, dai
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HOW TO MAKE GLOBALISATION MORE ‘FAIR’? The above evidence indicates that not everyone has benefited from globalisation. People with education, skill, and wealth have made the best use o
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WHAT IS CONSUMER RIGHT? This chapter proposes to discuss the issue of consumer rights within the context of the ways markets operate in our country. There are many aspects of unequal situations in
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RULES TO PROTECT CONSUMERS We participate in the market both as producers and consumers. As producers of goods and services we could be working in any of the sectors discussed earlier such as agric
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THE CONSUMER MOVEMENT – A ‘SOCIAL FORCE’ The consumer movement arose out of dissatisfaction of the consumers as many unfair practices were being indulged in by the sellers. There
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SAFETY IS EVERYONE’S RIGHT Reij's suffering Reji Mathew, a healthy boy studying in Class IX, was admitted in a private clinic in Kerala for the removal of tonsils. An ENT surgeon perfo
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INFORMATION ABOUT GOODS AND SERVICES When you buy any commodity, you will find certain details given on the packing. These details are about ingredients used, price, batch number, date of manufactu
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WHEN CHOICE IS DENIED Refund Abirami, a student of Ansari Nagar, joined a two year course at a local coaching institute for professional courses in New Delhi. At the time of joining the course,
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WHERE SHOULD CONSUMERS GO TO GET JUSTICE? Read again the cases of Reji Mathew and Abirami given earlier in the chapter. 1. Reji Mathew, a healthy boy studying in Class IX, was admitted
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LEARNING TO BECOME WELL-INFORMED CONSUMERS When we as consumers become conscious of our rights, while purchasing various goods and services, we will be able to discriminate
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ISI AND AGMERK While buying many commodities, on the cover, you might have seen a logo with the letters ISI, Agmark or Hallmark. These logos and certification help consumers get
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COPRA India has been observing 24 December as the National Consumers’ Day. It was on this day that the Indian Parliament enacted the Consumer Protection Act in 1986. India is one of the
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COMMUNITIES AND REGIONS Belgium is a small country in Europe, smaller in area than the state of Haryana. It has borders with France, the Netherlands, Germany, and Luxembourg. It has a population of
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MAJORITARIANISM IN SRI LANKA Sri Lanka emerged as an independent country in 1948. The leaders of the Sinhala community sought to secure dominance over the government by virtue of their majority. As
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ACCOMMODATION IN BELGIUM The Belgian leaders took a different path. They recognised the existence of regional differences and cultural diversities. Between 1970 and 1993, they amended their constit
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WHY POWER SHARING IS DESIRABLE? Thus, two different sets of reasons can be given in favour of power-sharing. 1. Power-sharing is good because it helps to reduce the possibility of co
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KHALIL’S DILEMMA As usual, Vikram was driving the motorbike under a vow of silence and Vetal was the pillion rider. As usual, Vetal started telling Vikram a story to keep him awake while driv
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IDEA OF POWER SHARING The idea of power-sharing has emerged in opposition to the notions of undivided political power. For a long time, it was believed that all power of a government must resi
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POWER SHARING AMONG ORGANS OF GOVERNMENT Power is shared among different organs of government, such as the legislature, executive, and judiciary. Let us call this horizontal distribution of power b
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POWER SHARING AT DIFFERENT LEVELS OF GOVERNMENT Power can be shared among governments at different levels – a general government for the entire country and governments at the provincial or
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POWER SHARING AMONG SOCIAL GROUPS Power may also be shared among different social groups such as the religious and linguistic groups. ‘Community government’ in Belgium is a good examp
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OTHER POWER SHARING ARRANGEMENTS Power-sharing arrangements can also be seen in the way political parties, pressure groups, and movements control or influence those in power. In a democracy, the
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WHAT IS FEDERALISM? Let us get back to the contrast between Belgium and Sri Lanka that we saw in the last chapter. You would recall that one of the key changes made in the Constitution of Belgium w
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PRINCIPLES OF FEDERALISM We have earlier seen how small countries like Belgium and Sri Lanka face so many problems of managing diversity. What about a vast country like India, with so many language
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LINGUISTIC STATES Constitutional provisions are necessary for the success of federalism but these are not sufficient. If the federal experiment has succeeded in India, it is not merely because of t
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LANGUAGE POLICY A second test for Indian federation is the language policy. Our Constitution did not give the status of national language to any one language. Hindi was identified as the official l
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CENTRE- STATE RELATIONS Restructuring the Centre-State relations is one more way in which federalism has been strengthened in practice. How the constitutional arrangements for sharing power work, i
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LINGUISTIC DIVERSITY OF INDIA How many languages do we have in India? The answer depends on how one counts it. The latest information that we have is from the Census of India held in 2011. Thi
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DECENTRALISATION – A MAJOR STEP We noted above that the federal government have two or more tiers of governments. We have so far discussed the two-tiers of government in our country. But a va
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AN EXPERIMENT IN BRAZIL A city called Porto Alegre in Brazil has carried out an extraordinary experiment in combining decentralisation with participative democracy. The city has set up a parallel o
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A STORY FROM MEXICO OLYMPICS The pictures on this page depict an important landmark in the history of the CIVIL RIGHTS MOVEMENT IN THE UNITED STATES. (Civil Rights Movement in the US
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ORIGIN OF SOCIAL DIFFERENCES The athletes in the example above were responding to social divisions and social inequalities. But does that happen only in societies which have racial divisions? In th
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OVERLAPPING AND CROSS-CUTTING DIFFERENCES Social division takes place when some social difference overlaps with other differences. The difference between Blacks and Whites becomes a social div
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RANGE OF OUTCOMES How do these social divisions affect politics? What does politics do to these social divisions? At first sight, it would appear that the combination of politics and social divisio
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BULGARIA, ROMANIA OR INDIA? Ganesh had come back from his trip and was talking to Mahashweta about the Roma people who live in many countries of Eastern Europe. He met Yordanka who works as
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THREE DETERMINANTS Three factors are crucial in deciding the outcome of politics of social divisions. 1. The outcome depends on how people perceive their identities. If people see t
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PUBLIC /PRIVATE DIVISION Let us begin with gender division. This is a form of hierarchical social division seen everywhere but is rarely recognised in the study of politics. The gender divisio
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DISCRIMINATION AND OPPRESSION OF WOMEN Political expression of gender division and political mobilisation on this question helped to improve women’s role in public life. We now find wome
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WOMEN AS ELECTED REPRESENTATIVES All this is well known. Yet issues related to women’s well-being or otherwise are not given adequate attention. This has led many feminists and women’s
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DIVISION BASED ON RELIGIOUS DIFFERENCES Let us now turn to a very different kind of social division, the division based on religious differences. This division is not as universal as gender, bu
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COMMUNALISM The problem begins when religion is seen as the basis of the nation. The example of Northern Ireland in Chapter 3 shows the dangers of such an approach to nationalism. The problem becom
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SECULAR STATE Communalism was and continues to be one of the major challenges to democracy in our country. The makers of our Constitution were aware of this challenge. That is why they chose the mo
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CASTE INEQUALITIES We have seen two instances of the expression of social divisions in the arena of politics, one largely positive and the other largely negative. Let us turn to our final case, tha
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SOCIAL AND RELIGIOUS DIVERSITY OF INDIA The Census of India records the religion of each and every Indian after every ten years. The person who fills the Census form visits every househol
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CASTE IN POLITICS As in the case of communalism, casteism is rooted in the belief that caste is the sole basis of the social community. According to this way of thinking, people belonging to the sa
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CASTE INEQUALITY TODAY Caste is an important source of economic inequality because it regulates access to resources of various kinds. For example, in the past, the so-called ‘untouchable&rsqu
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POLITICS IN CASTE We have so far looked at what caste does to politics. But it does not mean that there is only a one-way relation between caste and politics. Politics too influences the caste syst
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MOVEMENT FOR DEMOCRACY IN NEPAL Do you remember the story of the triumph of democracy in Poland? We studied it last year in the first chapter of class IX. The story reminded us about the role playe
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BOLIVIA’S WATER WAR The story of Poland and that of Nepal apply to the struggle for establishing or restoring democracy. But the role of popular struggles does not come to an end with the est
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DEMOCRACY AND POPULAR STRUGGLES These two stories are from very different contexts. The movement in Nepal was to establish democracy, while the struggle in Bolivia involved claims on an elected, de
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ROLE OF POLITICAL PARTIES AND ORGANISATIONS Let us go back to our two examples and look at the organisations that made these struggles successful. We noted that the call for indefinite strike was g
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SECTIONAL INTEREST GROUPS AND PUBLIC INTEREST GROUPS Pressure groups are organisations that attempt to influence government policies. But unlike political parties, pressure groups do not aim to dir
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MOVEMENT GROUPS As in the case of interest groups, the groups involved with movements also include a very wide variety. The various examples mentioned above already indicate a simple distinction. M
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HOW DO THEY INFLUENCE POLITICS? Pressure groups and movements exert influence on politics in a variety of ways: * They try to gain public support and sympathy for their goal
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IS THEIR INFLUENCE HEALTHY? It may initially appear that it is not healthy for groups that promote interest of one section to have influence in democracy. A democracy must look after the inte
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ELECTRIC CURRENT AND CIRCUIT Electricity has an important place in modern society. It is a controllable and convenient form of energy for a variety of uses in homes, schools, hospitals, industries
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WHAT IS ELECTRIC POTENTIAL AND POTENTIAL DIFFERENCE? Potential Difference What makes the electric charge to flow? Let us consider the analogy of the flow of water. Charges do not flow in a
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CIRCUIT DIAGRAM – A REPRESENTATION OF ELECTRIC CIRCUIT We know that an electric circuit, as shown in Fig. 12.1, comprises a cell (or a battery), a plug key, electrical component(s), and conne
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THE ROAD NOT TAKEN - ROBERT FROST (Poet) Poet This well-known poem is about making choices, and the choices that shape us. Robert Frost is an American poet who writes simply, but insightfully, a
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WIND - SUBRAMANIA BHARATI (Poet) Before you read The Poet of this poem is SUBRAMANIA BHARATI. Poem translated from Tamil by A.K. Ramanujan. Poet Subramania Bha
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RAIN ON THE ROOF - COATES KINNEY (Poet) Before you read When the sky is covered with dark clouds and it starts raining, have you ever listened to the patter of soft rain on the roof? What though
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THE LAKE ISLE OF INNISFREE - WILLIAM BUTLER YEATS (Poet) Before you read This well-known poem explores the poet’s longing for the peace and tranquillity of Innisfree, a place where he spen
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A LEGEND OF THE NORTHLAND - PHOEBE CARY (Poet) Before you read A ballad is a song narrating a story in short stanzas. Ballads are a part of the folk culture or popular culture and are passed on
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NO MEN ARE FOREIGN - JAMES KIRKUP (Poet) Before you read Have you ever thought of some people as strange, or other countries as ‘foreign’? We have many ways of thinking of other peop
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THE DUCK AND THE KANGAROO - EDWARD LEAR (Poet) Before you read This is a humorous poem of a kind known as ‘Nonsense Verse’, by Edward Lear. Read it and enjoy.
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ON KILLING A TREE - GIEVE PATEL (Poet) Before you read You must have observed people cutting down trees. But can they kill a tree? Is it easy to do so? Let’s read the poem and find out wha
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THE SNAKE TRYING - W. W. E. ROSS (Poet) Before you read Most of us think of snakes as fearsome symbols of death. But the snake in this poem is itself a victim. Poem The snake trying to
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A SLUMBER DID MY SPIRIT SEAL - WILLIAM WORDSWORTH (Poet) Before you read This poem is about the death of a loved one. How does the poet feel when he thinks about her death? How does he imagine h
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Before you read SCENE: A small cottage interior. There is an entrance back right (which may be curtained). Another door to the left must be a practical door. The furniture is simple, consisting of
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WHAT IS OHM’S LAW? Is there a relationship between the potential difference across a conductor and the current through it? Let us explore with an Activity. Activity 12.1: *&nb
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DEPENDING FACTORS OF RESISTANCE OF A CONDUCTOR Activity 12.3: * Complete an electric circuit consisting of a cell, an ammeter, a nichrome wire of length l [say, marked (1)], and
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COMBINATION OF RESISTORS In preceding sections, we learnt about some simple electric circuits. We have noticed how the current through a conductor depends upon its resistance and the potential diff
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RESISTORS IN SERIES What happens to the value of current when a number of resistors are connected in series in a circuit? What would be their equivalent resistance? Let us try to understand these w
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RESISTORS IN PARALLEL Now, let us consider the arrangement of three resistors joined in parallel with a combination of cells (or a battery), as shown in Fig.12.7 Figure 12.7: Resistors
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HOW HEATING EFFECT PRODUCED BY ELECTRIC CURRENT? We know that a battery or a cell is a source of electrical energy. The chemical reaction within the cell generates the potential difference between
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PRACTICAL APPLICATIONS The generation of heat in a conductor is an inevitable consequence of electric current. In many cases, it is undesirable as it converts useful electrical energy into heat. In
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WHAT IS ELECTRIC POWER? You have studied in your earlier Class that the rate of doing work is power. This is also the rate of consumption of energy. H = I2 Rt
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WHY DO WE NEED POLITICAL PARTIES? Political parties are easily one of the most visible institutions in a democracy. For most ordinary citizens, democracy is equal to political parties. If you trave
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MEANING OF POLITICAL PARTY A political party is a group of people who come together to contest elections and hold power in the government. They agree on some policies and programmes for the society
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WHAT DOES A POLITICAL PARTY DO? What does a political party do? Basically, political parties fill political offices and exercise political power. Parties do so by performing a series of functions:
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NECESSITY OF POLITICAL PARTY This list of functions in a sense answers the question asked above: we need political parties because they perform all these functions. But we still need to ask why mod
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POLITICAL PARTIES REGISTERED IN INDIA In a democracy, any group of citizens is free to form a political party. In this formal sense, there are a large number of political parties in each country. M
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A MORAL FORCE IN POLITICS The inspiration behind the following imaginary narrative is Shri Kishen Patnaik (1930–2004), also known as Kishenji. He was elected as a Member of Parliament from Sa
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POPULAR PARTICIPATION IN POLITICAL PARTIES It is often said that political parties are facing a crisis because they are very unpopular and the citizens are indifferent to political parties.
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WHAT ARE NATIONAL PARTIES? Democracies that follow a federal system all over the world tend to have two kinds of political parties: parties that are present in only one of the federal units and p
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DIFFERENT NATIONAL PARTIES According to this classification, there were seven recognised national parties in the country in 2018. Let us learn something about each of these parties. For more det
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WHAT ARE STATE PARTIES? Other than these seven parties, most of the major parties of the country are classified by the Election Commission as ‘State parties’. These are commonly referre
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LACK OF INTERNAL DEMOCRACY, DYNASTIC SUCCESSION Challenge to political parties We have seen how crucial political parties are for the working of democracy. Since parties are the most visible fac
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MONEY AND MUSCLE POWER, MEANINGFUL CHOICE Money and muscle power in parties The third challenge is about the growing role of money and muscle power in parties, especially during elections. Since
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FACING CHALLENGES BY REFORMING In order to face these challenges, political parties need to be reformed. The question is: Are political parties willing to reform? If they are willing, what has prev
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HOW DO WE ASSESS DEMOCRACY’S OUTCOMES? It emerged from that conversation that democracy is a better form of government when compared with dictatorship or any other alternative. We felt that d
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DEMOCRATIC VS NON-DEMOCRATIC GOVERNMENTS There are some things that democracy must provide. In a democracy, we are most concerned with ensuring that people will have the right to choose their ruler
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RATE OF ECONOMIC GROWTH If democracies are expected to produce good governments, then is it not fair to expect that they would also produce development? Evidence shows that in practice many democra
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ECONOMIC OUTCOMES OF DEMOCRACY Arguments about democracy tend to be very passionate. This is how it should be, for democracy appeals to some of our deep values. These debates cannot be resolved in
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EQUALITIES AND INEQUALITIES Perhaps more than development, it is reasonable to expect democracies to reduce economic disparities. Even when a country achieves economic growth, will wealth be distri
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ROLE OF DEMOCRACY IN SOCIAL DIVERSITY Do democracies lead to peaceful and harmonious life among citizens? It will be a fair expectation that democracy should produce a harmonious social life. We ha
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PROMOTING DIGNITY AND FREEDOM Democracy stands much superior to any other form of government in promoting dignity and freedom of the individual. Every individual wants to receive respect from fello
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INTRODUCTION In the previous Chapter on Electricity , we learnt about the heating effects of electric current. What could be the other effects of electric current? We know that an electri
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FINDING MAGNETIC FIELD AND FIELD LINES We are familiar with the fact that a compass needle gets deflected when brought near a bar magnet. A compass needle is, in fact, a small bar magnet. The ends
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HOW MAGNETIC FIELD IS CREATED? Activity 13.1: * Take a straight thick copper wire and place it between the points X and Y in an electric circuit, as shown in Fig. 13.1. The wire XY is
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MAGNETIC FIELD DUE TO A CURRENT THROUGH STRAIGHT CONDUCTOR What determines the pattern of the magnetic field generated by a current through a conductor? Does the pattern depend on the shape of the
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RIGHT-HAND THUMB RULE A convenient way of finding the direction of the magnetic field associated with a current-carrying conductor is given in Fig. 13.7. Figure 13.7: Right-hand thumb r
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MAGNETIC FIELD DUE TO A CURRENT THROUGH A CIRCULAR LOOP We have so far observed the pattern of the magnetic field lines produced around a current carrying straight wire. Suppose this straight wire
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MAGNETIC FIELD DUE TO A CURRENT IN SOLENOID A coil of many circular turns of insulated copper wire wrapped closely in the shape of a cylinder is called a solenoid. The pattern of the magnetic fie
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IMPACT OF FORCE IN MAGNETIC FIELD We have learnt that an electric current flowing through a conductor produces a magnetic field. The field so produced exerts a force on a magnet placed in the vicin
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ELECTRIC MOTOR An electric motor is a rotating device that converts electrical energy to mechanical energy. Electric motor is used as an important component in electric fans, refrigerators, mixers,
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ELECTROMAGNETIC INDUCTION We have studied that when a current-carrying conductor is placed in a magnetic field such that the direction of current is perpendicular to the magnetic field, it experien
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ELECTRIC GENERATOR Based on the phenomenon of electromagnetic induction, the experiments studied above generate induced current, which is usually very small. This principle is also employed to prod
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HOW DOMESTIC ELECTRIC CIRCUITS WORK? In our homes, we receive a supply of electric power through the main supply (also called mains), either supported through overhead electric poles or b
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INTRODUCTION In Class IX, we learnt that the total energy during a physical or chemical process is conserved. Why, then, do we hear so much about the energy crisis? If energy can neither
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DIFFERENT SOURCES OF ENERGY What can then be considered a good source of energy? We, in our daily lives, use energy from various sources for doing work. We use diesel to run our trains. We use elec
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FOSSIL FUELS Figure 14.1: Pie-chart showing the major sources of energy for our requirements in India In ancient times, wood was the most common source of heat energy. The ene
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THERMAL POWER AND HYDROPOWER PLANTS Thermal power plants Large amount of fossil fuels are burnt every day in power stations to heat up water to produce steam which further runs the turbine to ge
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BIOMASS We mentioned earlier that wood has been used as a fuel for a long time. If we can ensure that enough trees are planted, a continuous supply of fire-wood can be assured. You must also be fam
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WIND ENERGY We saw in Class IX how unequal heating of the landmass and water bodies by solar radiation generates air movement and causes winds to blow. This kinetic energy of the wind can be used t
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SOLAR ENERGY Alternative or non-conventional sources of energy With technological progress, our demand for energy increases day by day. Our lifestyles are also changing, we use machines to do mo
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ENERGY FROM THE SEA – TIDAL ENERGY, WAVE ENERGY, OCEAN THERMAL ENERGY Tidal Energy Due to the gravitational pull of mainly the moon on the spinning earth, the level of water in the sea ris
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GEOTHERMAL ENERGY Due to geological changes, molten rocks formed in the deeper hot regions of the earth’s crust are pushed upward and trapped in certain region called &lsq
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NUCLEAR ENERGY How is nuclear energy generated? In a process called nuclear fission, the nucleus of a heavy atom (such as uranium, plutonium or thorium), when bombarded with low-energy neutrons, ca
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EXPLOITING SOURCES OF ENERGY We have studied various sources of energy in the previous sections. Exploiting any source of energy disturbs the environment in some way or the other. In any given situ
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DEPLETION OF SOURCES OF ENERGY We saw earlier that we cannot depend on fossil fuels for much longer. Such sources that will get depleted someday are said to be exhaustible sources or non-ren
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SERIOUS PROBLEMS FACED BY DEMOCRACY Do you remember the chapters of your Political Science textbook of Class IX? There we tracked the expansion of democracy all over the world. Our reading thereaft
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CHALLENGES FOR DEMOCRACY IN DIFFERENT SITUATIONS Activity: A. Each of these cartoons represents a challenge to democracy. Please describe what that challenge is. 1. Mubarak
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TYPES OF CHALLENGES Activity: A. Now that you have noted down all these challenges, let us group these together into some broad categories. Given below are some spheres or sites of d
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REFORMS TO OVERCOME CHALLENGES Each of these challenges is linked to the possibility of reforms. As mentioned above, we discuss challenges only because we think these can be overcome. Generally all
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DOCTOR’S ABSENTEEISM VS POLITICAL FUNDING Here are some challenges that require political reforms. Discuss these challenges in detail. Study the reform options offered here and give your pref
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REFORMING POLITICS Rose managed to catch Madam Lyngdoh outside the classroom, something she had been planning to do for some time. “Ma’am! I really liked that Ca
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REDEFINING DEMOCRACY We began this tour of democracy last year with a minimal definition of democracy. Do you remember that? This is what Chapter 2 of your textbook said last year: democracy is a f
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INTRODUCTION You have already learned earlier that India is a vast country with varied landforms. What kind of terrain do you live in? If you live in the plains, you are familiar with the
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INTRODUCTION AND MAJOR GROUPS OF DRAINAGE SYSTEM The term drainage describes the river system of an area. Look at the physical map. You will notice that small streams flowing from differe
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THE INDUS RIVER SYSTEM The major Himalayan rivers are the Indus, the Ganga and the Brahmaputra. These rivers are long and are joined by many large and important tributaries. A river along with
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THE GANGA RIVER SYSTEM The headwaters of the Ganga, called the ‘Bhagirathi’ is fed by the Gangotri Glacier and joined by the Alaknanda at Devaprayag in Uttarakhand. At Haridwar, the Gan
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THE BRAHMAPUTRA RIVER SYSTEM The Brahmaputra rises in Tibet east of Mansarowar lake very close to the sources of the Indus and the Satluj. It is slightly longer than the Indus, and most of its cour
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THE NARMADA AND TAPI BASIN The Peninsular Rivers The main water divide in Peninsular India is formed by the Western Ghats, which runs from north to south close to the western coast. Most of the
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THE GODAVARI AND MAHANADI BASIN The Godavari Rivers The Godavari is the largest Peninsular river. It rises from the slopes of the Western Ghats in the Nasik district of Maharashtra. Its length i
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THE KRISHNA AND KAVERI BASIN The Krishna Rivers Rising from a spring near Mahabaleshwar, the Krishna flows for about 1400 km and reaches the Bay of Bengal. The Tungabhadra, the Koyana, the Ghatp
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LAKES – TYPES, SIZE AND CHARACTERISTICS You may be familiar with the valley of Kashmir and the famous Dal Lake, the house boats and shikaras, which attract thousands of tourists every year. S
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ROLE OF RIVERS IN ECONOMY AND RIVER POLLUTION Role of rivers in economy Rivers have been of fundamental importance throughout the human history. Water from rivers is a basic natural resource, es
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GEOGRAPHY LESSON - ZULFIKAR GHOSE (Poet) Can you imagine what your city would look like if you saw it from ten thousand feet above the ground? Neatly planned and perfect in proportion like a geomet
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CLIMATE AND WEATHER In the last two chapters you have read about the landforms and the drainage of our country. These are two of the three basic elements that one learns about the natural envi
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MAJOR CONTROLS OF CLIMATE There are six major controls of the climate of any place. They are: latitude, altitude, pressure and wind system, distance from the sea (continentality), ocean currents an
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FACTORS AFFECTING INDIA’S CLIMATE Latitude The Tropic of Cancer passes through the middle of the country from the Rann of Kuchchh in the west to Mizoram in the east. Almost half of the cou
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UNDERSTANDING MECHANISM OF MONSOON The climate of India is strongly influenced by monsoon winds. The sailors who came to India in historic times were one of the first to have noticed the phenomenon
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MONSOON- PULSATING IN NATURE The Monsoon, unlike the trades, are not steady winds but are pulsating in nature, affected by different atmospheric conditions encountered by it, on its way over the wa
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THE COLD WEATHER SEASON (WINTER) The monsoon type of climate is characterised by a distinct seasonal pattern. The weather conditions greatly change from one season to the other. These changes are p
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THE HOT WEATHER SEASON (SUMMER) Due to the apparent northward movement of the sun, the global heat belt shifts northwards. As such, from March to May, it is a hot weather season in I
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ADVANCING MONSOON (THE RAINY SEASON) By early June, the low-pressure condition over the northern plains intensifies. It attracts the trade winds of the southern hemisphere. These south-east tr
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RETREATING /POST MONSOON (THE TRANSITION SEASON) During October-November, with the apparent movement of the sun towards the south, the monsoon trough or the low-pressure trough over the northern pl
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DISTRIBUTION OF RAINFALL Parts of the western coast and northeastern India receive over about 400 cm of rainfall annually. However, it is less than 60 cm in western Rajasthan and adjoining parts of
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MONSOON AS AN UNIFYING BOND You have already known the way the Himalayas protect the subcontinent from extremely cold winds from central Asia. This enables northern India to have uniformly higher t
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WHAT IS VIRGIN VEGETATION AND FLORA AND FAUNA? Have you observed the type of trees, bushes, grasses and birds in the fields and parks in and around your school? Are they similar o
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LAND AND SOIL Land Land affects the natural vegetation directly and indirectly. Do you expect the same type of vegetation in mountainous, plateau and plain areas or in dry and wet regions? The n
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TEMPERATURE, PHOTOPERIOD(SUNLIGHT) AND PRECIPITATION Temperature The character and extent of vegetation are mainly determined by temperature along with humidity in the air, precipitation and soi
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TROPICAL EVERGREEN FORESTS Types of vegetation The following major types of vegetation may be identified in our country (Figure 5.3). Figure 5.3: Natural Vegetation &nbs
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TROPICAL DECIDUOUS FORESTS These are the most widespread forests of India. They are also called the monsoon forests and spread over the region receiving rainfall between 200 cm and 70 cm. Trees of
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THE THORN FORESTS AND SCRUBS In regions with less than 70 cm of rainfall, the natural vegetation consists of thorny trees and bushes. This type of vegetation is found in the north-western part of t
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MONTANE FORESTS In mountainous areas, the decrease in temperature with increasing altitude leads to the corresponding change in natural vegetation. As such, there is a succession of natural vegetat
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MANGROVE FORESTS The mangrove tidal forests are found in the areas of coasts influenced by tides. Mud and silt get accumutated on such coasts. Dense mangroves are the common varieties with roots of
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WILDLIFE IN INDIA Like its flora, India is also rich in its fauna. It has approximately 90,000 animal species. The country has about 2,000 species of birds. They constitute 13% of the world’s
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STEPS TO PROTECT THE FLORA AND FAUNA To protect the flora and fauna of the country, the government has taken many steps. i. Eighteen biosphere reserves have been set up in
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INTRODUCTION Can you imagine a world without human beings? Who would have utilised the resources and created social and cultural environment? The people are important to develop the economy an
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SIZE, DISTRIBUTION BY NUMBERS AND BY DENSITY India’s Population Size and Distribution by Numbers India’s population as on March 2011 stood at 1,210.6 million, which account
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POPULATION GROWTH Population growth and processes of population change Population is a dynamic phenomenon. The numbers, distribution and composition of the population are constantly ch
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PROCESS OF POPULATION CHANGE/GROWTH There are three main processes of change of population : i. birth rates, ii. death rates and iii. migration. The
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AGE COMPOSITION AND SEX RATIO The age composition of a population refers to the number of people in different age groups in a country. It is one of the most basic characteristics of a population. T
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LITERACY RATES AND OCCUPATIONAL STRUCTURE Literacy Rates Literacy is a very important quality of a population. Obviously, only an informed and educated citizen can make intelligent cho
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HEALTH Health is an important component of population composition, which affects the process of development. Sustained efforts of government programmes have registered significant improvements in t
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ADOLESCENT POPULATION AND NATIONAL POPULATION POLICY Adolescent Population The most significant feature of the Indian population is the size of its adolescent population. It constitute
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WHY DEFINE DEMOCRACY? You have already read about different forms of government. On the basis of your understanding of democracy so far, mentioning a few examples write down some common f
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A SIMPLE DEFINITION Let us get back to our discussion on similarities and differences among governments that are called democracies. One simple factor common to all democracies is: the governm
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QUESTIONS RAISED We have started with a simple definition that democracy is a form of government in which the rulers are elected by the people. This raises many questions: *&
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MAJOR DECISIONS BY ELECTED LEADERS In Pakistan, General Pervez Musharraf led a military coup in October 1999. He overthrew a democratically elected government and declared himself the &ls
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FREE AND FAIR ELECTORAL COMPETITION In China, elections are regularly held after every five years for electing the country’s parliament, called Quanguo Renmin Daibiao Dahui (National People&r
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ONE PERSON, ONE VOTE, ONE VALUE Earlier, we read about how the struggle for democracy was linked to the demand for a universal adult franchise. This principle has now come to be accepted almos
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RULE OF LAW AND RESPECT FOR RIGHTS Zimbabwe attained independence from White minority rule in 1980. Since then the country has been ruled by ZANU-PF, the party that led the freedom strugg
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DEBATING MERITS OF DEMOCRACY An argument broke out in Madam Lyngdoh’s class. She had finished teaching the previous section on what is democracy and asked the students if they thoug
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ARGUMENTS AGAINST DEMOCRACY This conversation has most of the arguments that we routinely hear against democracy. Let us go over some of these arguments: * Leaders ke
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ARGUMENTS FOR DEMOCRACY China’s famine of 1958-1961 was the worst recorded famine in world history. Nearly three crore people died in this famine. During those days, India’s e
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BROADER MEANING OF DEMOCRACY In this chapter, we have considered the meaning of democracy in a limited and descriptive sense. We have understood democracy as a form of government. Th
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OVERVIEW We noted in the previous chapter that in a democracy the rulers are not free to do what they like. There are certain basic rules that the citizens and the government have to foll
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STRUGGLES AGAINST APARTHEID “I have fought against white domination and I have fought against black domination. I have cherished the ideal of a democratic and free society in which
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TOWARDS A NEW CONSTITUTION As protests and struggles against apartheid had increased, the government realised that they could no longer keep the blacks under their rule through repression
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NEED OF CONSTITUTION The South African example is a good way to understand why we need a constitution and what do constitutions do. The oppressor and the oppressed in this new democracy w
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THE PATH TO CONSTITUTION Like South Africa, India’s Constitution was also drawn up under very difficult circumstances. The making of the constitution for a huge and diverse country
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THE CONSTITUENT ASSEMBLY Who, then, were the makers of the Indian Constitution? You will find here a very brief sketch of some of the leaders who played an important role in making the Constit
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THE DREAM AND THE PROMISE In this book, we shall study the exact provisions of the Constitution on different subjects. At this stage let us begin by understanding the overall philosophy of wha
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PHILOSOPHY OF THE CONSTITUTION Values that inspired and guided the freedom struggle and were in turn nurtured by it, formed the foundation for India’s democracy. These values are embedded in
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INSTITUTIONAL DESIGN A constitution is not merely a statement of values and philosophy. As we noted above, a constitution is mainly about embodying these values into institutional arrangements. Muc
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OVERVIEW In Chapter 1 we have seen that in a democracy it is neither possible nor necessary for people to govern directly. The most common form of democracy in our times is for the people to govern
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ASSEMBLY ELECTION IN HARYANA This newspaper report is about the state assembly election in Haryana in 1987. The State had been ruled by a Congress party-led government since 1982
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WHY DO WE NEED ELECTIONS? Elections take place regularly in any democracy. There are more than one hundred countries in the world in which elections take place to choose people’s re
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WHAT MAKES AN ELECTION DEMOCRATIC? Elections can be held in many ways. All democratic countries hold elections. But most non-democratic countries also hold some kind of elections. How do we disting
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IS IT GOOD TO HAVE POLITICAL COMPETITION? Elections are thus all about political competition. This competition takes various forms. The most obvious form is competition among political parties
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ELECTORAL CONSTITUENCIES Can we say that Indian elections are democratic? To answer this question, let us take a look at how elections are held in India. Lok Sabha and Vidhan Sabha (Assembly) elect
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RESERVED CONSTITUENCIES Our Constitution entitles every citizen to elect her/his representative and to be elected as a representative. The Constitution makers, however, were worried that in an
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VOTER’S LIST Once the constituencies are decided,the next step is to decide who can and who cannot vote. This decision cannot be left to anyone till the last day. In a democratic election, th
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NOMINATION OF CANDIDATES We noted above that in a democratic election people should have a real choice. This happens only when there are almost no restrictions on anyone to contest an election
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ELECTION CAMPAIGN The main purpose of election is to give people a chance to choose the representatives, the government and the policies they prefer. Therefore it is necessary to have a free and op
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POLLING AND COUNTING OF VOTES The final stage of an election is the day when the voters cast or ‘poll’ their vote. That day is usually called the election day. Every person whose name i
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INDEPENDENT ELECTION COMMISSION We get to read a lot about unfair practices in elections. Newspapers and television reports often refer to such allegations. Most of these reports are about the foll
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POPULAR PARTICIPATION Another way to check the quality of the election process is to see whether people participate in it with enthusiasm. If the election process is not free or fair, people w
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ACCEPTANCES OF ELECTION OUTCOME One final test of the free and fairness of election has in the outcome itself. If elections are not free or fair, the outcome always favours the powerful.
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CHALLENGE TO FREE AND FAIR ELECTIONS All this leads to a simple conclusion: elections in India are basically free and fair. The party that wins an elec- tion and forms government does so because pe
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INTRODUCTION As we look at our surroundings, we see a large variety of things with different shapes, sizes and textures. Everything in this universe is made up of material that scientists have name
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MATTER IS MADE UP OF PARTICLES For a long time, two schools of thought prevailed regarding the nature of matter. One school believed matter to be continuous like a block of wood, whereas, the other
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HOW SMALL ARE THESE PARTICLES OF MATTER? Activity 1.2: ( Particles of matter are small ) * Take 2-3 crystals of potassium permanganate and dissolve them in 100 mL of water. *
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SPACE BETWEEN PARTICLES OF MATTER Activity 1.1: ( Space between particles of Matter ) * Take a 100 mL beaker. * Fill half the beaker with water and mark t
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MOTION OF PARTICLES OF MATTER Activity 1.3: ( Experiment with incense stick ) * Put an unlit incense stick in a corner of your class. How close do you have to go near it so
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ATTRACTION BETWEEN PARTICLES OF MATTER Activity 1.6: * Play this game in the field— make four groups and form human chains as suggested: * The first group should h
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INTRODUCTION OF STATES OF MATTER Observe different types of matter around you. What are its different states? We can see that matter around us exists in five different states– i. &n
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THE SOLID STATE Activity 1.9: * Collect the following articles— a pen, a book, a needle and a piece of wooden stick. * Sketch the shape of the above articles in
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THE LIQUID STATE Activity 1.10: * Collect the following: a. water, cooking oil, milk, juice, a cold drink. &nbs
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THE GASEOUS STATE Have you ever observed a balloon seller filling a large number of balloons from a single cylinder of gas? Enquire from him how many balloons is he able to fill from one cylinder.
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PLASMA The state consists of super energetic and super excited particles. These particles are in the form of ionised gases. The fluorescent tube and neon sign bulbs consist of plasma. Inside a neon
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BOSE-EINSTEIN CONDENSATE In 1920, Indian physicist Satyendra Nath Bose had done some calculations for the fifth state of matter. Building on his calculations, Albert Einstein predicted a new s
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EFFECT OF CHANGE OF TEMPERATURE We all know from our observation that water can exist in three states of matter– * solid, as ice, * liquid, as th
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EFFECT OF CHANGE OF PRESSURE We have already learnt that the difference in various states of matter is due to the difference in the distances between the constituent particles. What will happen whe
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WHAT IS EVAPORATION Do we always need to heat or change pressure for changing the state of matter? Can you quote some examples from everyday life where change of state from liquid to vapour takes p
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FACTORS AFFECTING EVAPORATION Let us understand this with an activity. Activity 1.14: ( Activity showing factors affecting evaporation ) * Take 5 mL of water in a test t
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HOW DOES EVAPORATION CAUSE COOLING? In an open vessel, the liquid keeps on evaporating. The particles of liquid absorb energy from the surrounding to regain the energy lost during evaporation. This
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INTRODUCTION TO PURE SUBSTANCE How do we judge whether milk, ghee, butter, salt, spices, mineral water or juice that we buy from the market are pure? Figure 2.1: Some consumab
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WHAT IS MIXTURE Mixtures are constituted by more than one kind of pure form of matter. We know that dissolved sodium chloride can be separated from water by the physical process of e
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TYPES OF MIXTURE Depending upon the nature of the components that form a mixture, we can have different types of mixtures. Activity 2.1: ( Homogeneous mixtures and Heterogene
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WHAT IS SOLUTION? A solution is a homogeneous mixture of two or more substances. You come across various types of solutions in your daily life. Lemonade, soda water etc. are all examples
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PROPERTIES OF SOLUTION * A solution is a homogeneous mixture. * The particles of a solution are smaller than 1 nm (10-9 metre) in diameter. So, they cannot be seen by nak
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WHAT IS A SUSPENSION? Activity 2.2: * Let us again divide the class into four groups – A, B, C and D. * Distribute the following samples to each group:
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WHAT IS A COLLOIDAL SOLUTION? The mixture obtained by group D in the activity is called a colloid or a colloidal solution. The particles of a colloid are uniformly spread throughout the s
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PROPERTIES OF COLLOIDAL SOLUTION * A colloid is a heterogeneous mixture. * The size of particles of a colloid is too small to be individually seen by naked eyes. *&nbs
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UNSATURATED AND SATURATED SOLUTION Saturated solution Activity 2.2: * Let us again divide the class into four groups – A, B, C, and D. * D
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SOLUBILITY The amount of the solute present in the saturated solution at this temperature is called its solubility. We can infer from the above activity that different substances in
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MASS BY MASS PERCENTAGE Mass by mass percentage of a solution = \(\frac{mass \,\,of\,\, solute}{mass \,\,of \,\,solution}\,\,\times\,\,100\) Note: A solution is a homogeneous mixture of
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VOLUME BY VOLUME PERCENTAGE Volume by volume percentage of a solution = \(\frac{volume \,\,of\,\, solute}{volume \,\,of \,\,solution}\,\,\times\,\,100\) Note: A solution is a homogeneous
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MASS BY VOLUME PERCENTAGE Mass by volume percentage of a solution = \(\frac{mass \,\,of\,\, solute}{volume \,\,of \,\,solution}\,\,\times\,\,100\) Note: A solution is a homogeneous
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SEPARATION OF HETEROGENEOUS MIXTURES We have learnt that most of the natural substances are not chemically pure. Different methods of separation are used to get individual components from a mixture
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SEPARATION OF COLOURED COMPONENTS IN A DYE Activity 2.4: (Separation by evaporation) * Fill half a beaker with water. * Put a watch glass on the mouth of the beaker (Fig
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SEPARATION OF CREAM FROM MILK Now-a-days, we get full-cream, toned and double-toned varieties of milk packed in poly- packs or tetra packs in the market. These varieties of milk contain different a
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SEPARATION OF MIXTURES OF TWO IMMISCIBLE LIQUIDS Now-a-days, we get full-cream, toned, and double-toned varieties of milk packed in poly- packs or tetra packs in the market. These varieties of
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SEPARATION OF MIXTURES OF SALT AND CAMPHOR We have learned in chapter 1 that camphor changes directly from solid to gaseous state on heating. So, to separate such mixtures that contain a sublimable
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SEPARATION OF DYES USING CHROMATOGRAPHY * Take a thin strip of filter paper. * Draw a line on it using a pencil, approximately 3 cm above the lower edge [Fig. 2.8 (a)].
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SEPARATION OF MIXTURES OF TWO MISCIBLE LIQUIDS Activity: (Separating Miscible liquid mixtures) * Let us try to separate acetone and water from their mixture. *  
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SEPARATION OF DIFFERENT GASES FROM AIR Separation of components of air Air is a homogeneous mixture and can be separated into its components by fractional distillation. The flow diagram (Fig. 2.
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SEPARATION OF PURE COPPER SULPHATE FROM IMPURE SAMPLE – CRYSTALLISATION Activity 2.9: (Crystallisation) * Take some (approximately 5 g) impure sample of copper sulphate in a chi
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WATER PURIFICATION SYSTEM In cities, drinking water is supplied from water works. A flow diagram of a typical water works is shown in Fig. 2.13. From this figure write down the processes involved t
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WHAT IS PHYSICAL AND CHEMICAL CHANGE? In the previous chapter, we have learnt about a few physical properties of matter. The properties that can be observed and specified like colour, hardness, rig
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ELEMENTS On the basis of their chemical composition, substances can be classified either as elements or compounds. Robert Boyle was the first scientist to use the term element in 1661. Antoine L
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COMPOUNDS A compound is a substance composed of two or more elements, chemically combined with one another in a fixed proportion. What do we get when two or more elements are combined? Activi
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DIFFERENCE BETWEEN COMPOUNDS AND MIXTURES Thus, we can summarise the physical and chemical nature of matter in the following graphical organiser : S
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HISTORY OF ATOMS AND MOLECULES Ancient Indian and Greek philosophers have always wondered about the unknown and unseen form of matter. The idea of divisibility of matter was considered long back in
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LAW OF CONSERVATION OF MASS The following two laws of the chemical combination were established after much experimentations by Lavoisier and Joseph L. Proust. Is there a change in mass when
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LAW OF CONSTANT PROPORTIONS Lavoisier , along with other scientists, noted that many compounds were composed of two or more elements and each such compound had the same elements in the same pr
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DALTON’S ATOMIC THEORY According to Dalton’s atomic theory, all matter, whether an element, a compound, or a mixture is composed of small particles called atoms. The postulates of this
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WHAT IS AN ATOM? Have you ever observed a mason building walls, from these walls a room and then a collection of rooms to form a building? What is the building block of the huge building? What abou
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SYMBOLS OF ATOMS Dalton was the first scientist to use symbols for elements in a very specific sense. When he used a symbol for an element he also meant a definite quantity of that element, th
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WHAT IS ATOMIC MASS? The most remarkable concept that Dalton’s atomic theory proposed was that of atomic mass. According to him, each element had a characteristic atomic mass. The theory
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HOW DO ATOMS EXIST? Atoms of most elements are not able to exist independently. Atoms form molecules and ions. These molecules or ions aggregate in large numbers to form the matter that we can see,
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MOLECULES OF ELEMENTS AND ATOMICITY The molecules of an element are constituted by the same type of atoms. Molecules of many elements, such as argon (Ar), helium (He), etc. are made up of only one
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MOLECULES OF COMPOUNDS Atoms of different elements join together in definite proportions to form molecules of compounds. Few examples are given in Table. * Refer to Table 
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WHAT IS AN ION? Compounds composed of metals and non-metals contain charged species. The charged species are known as ions. Ions may consist of a single charged atom or a group of atoms that have a
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POLYATOMIC ION A group of atoms carrying a charge is known as a polyatomic ion (Table). We shall learn more about the formation of ions in Chapter 4.
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CONCEPT OF VALENCY The chemical formula of a compound is a symbolic representation of its composition. The chemical formulae of different compounds can be written easily. For this exercise, we need
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RULES FOR WRITING CHEMICAL FORMULA The rules that you have to follow while writing a chemical formula are as follows: * the valencies or charges on the ion must balance. *&nbs
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FORMULAE OF SIMPLE COMPOUNDS The simplest compounds, which are made up of two different elements are called binary compounds. Valencies of some ions are given in Table 3.6. You can use these to wri
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WHAT IS MOLECULAR MASS? The atomic mass (ma or m) is the mass of an atom. Although the SI unit of mass is the kilogram (symbol: kg), the atomic mass is often expr
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WHAT IS FORMULA UNIT MASS? The Formula unit mass of a substance is a sum of the atomic masses of all atoms in a formula unit of a compound. Formula unit mass is calculated in the same manner as we
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WHAT IS A MOLE? Take an example of the reaction of hydrogen and oxygen to form water: 2H2
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RELATIONSHIP BETWEEN MOLE, AVOGADRO NUMBER AND ATOMIC NUMBER AND ATOMIC MASS Mole One mole contains exactly 6.02214076\(\times\)1023 elementary entities. This number is the fixed numerical
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CHALLENGE BEFORE THE SCIENTISTS In Chapter 3, we have learnt that atoms and molecules are the fundamental building blocks of matter. The existence of different kinds of matter is due to different a
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ELECTRON For understanding the nature of charged particles in matter, let us carry out the following activities: Activity 4.1: A. Comb dry hair. Does the comb then attract sma
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PROTON E. Goldstein in 1886 discovered the presence of new radiations in a gas discharge and called them canal rays. These rays were positively charged radiations which ultimately led to the discov
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NEUTRON A neutron is a sub-atomic particle with no net electrostatic charge, with a very similar mass to a proton. Neutrons are thought to comprise of one up quark&nbs
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DALTON’S ATOMIC THEORY It seemed that an atom was composed of protons and electrons, mutually balancing their charges. It also appeared that the protons were in the interior of the atom, for
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THOMSON ATOMIC MODEL Thomson proposed the model of an atom to be similar to that of a Christmas pudding. The electrons, in a sphere of positive charge, were like currants (dry fruits) in a spherica
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DRAWBACKS OF THOMSON’S MODEL OF AN ATOM Although Thomson's model explained that atoms are electrically neutral, the results of experiments carried out by other scientists could not b
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EXPERIMENT Ernest Rutherford was interested in knowing how the electrons are arranged within an atom. Rutherford designed an experiment for this. In this experiment, fast-moving alpha(\(\alpha\))-p
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OBSERVATIONS But, the \(\alpha\)-particle scattering experiment gave totally unexpected results (Fig. 4.2). The following observations were made: * Most of the fast-moving &nbs
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CONCLUSIONS Following similar reasoning, Rutherford concluded from the \(\alpha\)-particle scattering experiment that– i. Most of the space inside the atom is empty becau
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DRAWBACKS The revolution of the electron in a circular orbit is not expected to be stable. Any particle in a circular orbit would undergo acceleration. During acceleration, charged particles would
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POSTULATES OF BOHR’S MODEL In order to overcome the objections raised against Rutherford model of the atom, Neils Bohr put forward the following postulates about the model of an atom: i.&n
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DRAWBACKS OF BOHR’S MODEL It doesn't explain about the energy of an atom and it's stability. * Heisenberg principle - Position and momentum of a particle cannot be dete
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DISTRIBUTION OF ELECTRONS IN DIFFERENT ORBITS(SHELLS) The distribution of electrons into different orbits of an atom was suggested by Bohr and Bury. The following rules are followed fo
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VALENCE ELECTRONS A valence electron is a negatively charged particle, located in the outermost shell of an atom that can be transferred to or shared with another atom. valence(o
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CONCEPT OF VALENCY The number of electrons gained, lost or shared so as to make the octet of electrons in the outermost shell, gives us directly the combining capacity of the element, that is,
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BOHR-BURY SCHEME From the Bohr-Bury scheme, we also know that the outermost shell of an atom can accommodate a maximum of 8 electrons. It was observed that the atoms of elements, completely fi
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ATOMIC NUMBER We know that protons are present in the nucleus of an atom. It is the number of protons of an atom, which determines its atomic number. It is denoted by ‘Z’. All atoms of
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MASS NUMBER After studying the properties of the sub- atomic particles of an atom, we can conclude that mass of an atom is practically due to protons and neutrons alone. These are present in the nu
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ISOTOPES In nature, a number of atoms of some elements have been identified, which have the same atomic number but different mass numbers. For example, take the case of hydrogen atom, it has three
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ISOBARS Let us consider two elements — calcium,atomic number 20, and argon, atomic number 18. The number of protons in these atoms is different, but the mass number of both the
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NATURAL AND ARTIFICIAL FIBRES The clothes which we wear are made of fabrics. Fabrics are made from fibres obtained from natural or artificial sources. Can you name some natural fibres? F
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WHAT ARE SYNTHETIC FIBRES Try to recall the uniform pattern found in a necklace of beads joined with the help of a thread [Fig. 3.1(a)]. Or, try to join a number of paper clips together to make a l
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RAYON You have read in Class VII that silk fibre obtained from silkworm was discovered in China and was kept as a closely guarded secret for a long time. Fabric obtained from silk fibre was very co
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NYLON Nylon is another man-made fibre. In 1931, it was made without using any natural raw material (from plants or animals). It was prepared from coal, water and air. It was the first fully synthet
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POLYESTER AND ACRYLIC Polyester is another synthetic fibre. Fabric made from this fibre does not get wrinkled easily. It remains crisp and is easy to wash. So, it is quite suitable for making dress
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SYNTHETIC FIBRES IN EVERYDAY LIFE Imagine that it is a rainy day. What kind of umbrella would you use and why? Synthetic fibres possess unique characteristics which make them popular dress mat
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ROLE OF PLASTICS IN EVERYDAY LIFE You must be familiar with many plastic articles used everyday. Make a list of such items and their uses. Figure 3.6: (a) Linear (b) Cross-lin
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THERMOPLASTICS AND THERMOSETTING PLASTICS Thermoplastics Plastic which gets deformed easily on heating and can be bent easily are known as thermoplastics. Polythene and PVC are some of the examp
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Plastics as materials of choice PLASTIC IS NON-REACTIVE Today if we think of storing a food item, water, milk, pickles, dry food, etc., plastic containers seem most convenient. This is
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Plastic is light, strong and durable Talk to your parents or grandparents about the types of buckets that were used in the past. What is the material of the buckets or mugs you are using
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PLASTICS ARE POOR CONDUCTORS You have learned above that plastics are poor conductors of heat and electricity. That is why electrical wires have plastic covering, and the handles of screw
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BIODEGRADABLE PLASTICS When we go to the market, we usually get things wrapped in plastic or packed in polythene bags. That is one reason why plastic waste keeps getting accumulated in ou
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NON-BIODEGRADABLE PLASTICS A material which is not easily decomposed by natural processes is termed non-biodegradable. Since plastic takes several years to decompose, it is not environ
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5R PRINCIPLE As a responsible citizen remember the 5 R principle. Reduce, Reuse, Recycle, Recover and Refuse. Develop habits which are environment friendly. More to know * &nbs
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WHAT ARE MATERIALS? You are familiar with a number of materials like iron, aluminium, copper, etc. Some materials have been given in Table 4.1. Table 4.1: Appearance and Hardness o
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PHYSICAL PROPERTIES OF METALS Have you ever seen a blacksmith beating an iron piece or an article made up of iron, like a spade, a shovel, an axe? Do you find a change in the shape of these article
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PHYSICAL PROPERTIES OF NON METALS In contrast, materials like coal and sulphur are soft and dull in appearance. They break down into a powdery mass on tapping with a hammer. They are not sonorous a
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REACTION WITH OXYGEN You are familiar with the phenomenon of rusting of iron. Recall the reaction by which rust is formed. You had also performed in Class VII activity of burning a magnes
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REACTION WITH WATER Let us see how metals and non-metals react with water. Sodium metal is very reactive. It reacts vigorously with oxygen and water. A lot of heat is generated in the reaction.
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REACTION WITH ACIDS Let us see how metals and non-metals behave with acids. Activity 4.6: (Warning : Keep the mouth of the test tube away from your face. Use test tube holder to hol
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REACTION WITH BASES Activity 4.7: (To be demonstrated by the teacher. During the preparation of sodium hydroxide solution, care should be taken that pellets of sodium hydroxide are handled with
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DISPLACEMENT REACTIONS Activity 4.8: * Recall the activity of the reaction between copper sulphate and iron that you performed in Class VII. * Let us observe som
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USES OF METALS AND NON-METALS IN DAILY LIFE You should be able to guess why metals are used in making machinery, automobiles, aeroplanes, trains, satellites, industrial gadgets, cooking utensils, w
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WHAT ARE NATURAL RESOURCES? We use various materials for our basic needs. Some of them are found in nature and some have been made by human efforts. Activity 5.1: Make a list o
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INEXHAUSTIBLE NATURAL RESOURCES These resources are present in unlimited quantity in nature and are not likely to be exhausted by human activities. Examples are: sunlight, air.
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EXHAUSTIBLE NATURAL RESOURCES The amount of these resources in nature is limited. They can be exhausted by human activities. Examples of these resources are forests, wildlife, minerals, coal, petro
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STORY OF COAL You may have seen coal or heard about it (Fig. 5.1). It is as hard as stone and is black in colour. Figure 5.1: Coal Coal is one of the fuels used to cook foo
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COKE It is a tough, porous and black substance. It is an almost pure form of carbon. Coke is used in the manufacture of steel and in the extraction of many metals.
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COAL TAR It is a black, thick liquid (Fig. 5.3) with an unpleasant smell. It is a mixture of about 200 substances. Products obtained from coal tar are used as starting materials for manufactur
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COAL GAS Coal gas is obtained during the processing of coal to get coke. It is used as a fuel in many industries situated near the coal processing plants. Coal gas was used for street lig
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FORMATION OF PETROLEUM You know that petrol is used as a fuel in light automobiles such as motor cycles/ scooters and cars. Heavy motor vehicles like trucks and tractors run on diesel. Petrol and d
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REFINING OF PETROLEUM Petroleum is a dark oily liquid. It has an unpleasant odour. It is a mixture of various constituents such as petroleum gas, petrol, diesel, lubricating oil, paraffin wax, etc.
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NATURAL GAS(CNG) Natural gas is a very important fossil fuel because it is easy to transport through pipes. Natural gas is stored under high pressure as compressed natural gas (CNG). CNG is used fo
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WHY SOME NATURAL RESOURCES ARE LIMITED? You have studied in the beginning of the chapter that some natural resources are exhaustible like fossil fuels, forests, minerals etc. You know
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USE OF FUEL IN DAILY LIFE We use different kinds of fuel for various purposes at home, in industry and for running automobiles. Can you name a few fuels used in our homes? Name a few fuels used in
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WHAT IS COMBUSTION Recall the activity of burning of magnesium ribbon performed in Class VII. We learnt that magnesium burns to form magnesium oxide and produces heat and light (Fig. 6.1). We
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COMBUSTIBLE AND NONCOMBUSTIBLE SUBSTANCES In the reactions mentioned above magnesium and charcoal are combustible substances. Activity 6.1: Collect some materials like straw, m
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IGNITION TEMPERATURE * Now recall some of your experiences. Does a matchstick burn by itself? How does it burn? * You must have had an experience of burning a piece of paper. Do
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HISTORY OF MATCHSTICK The history of the matchstick is very old. More than five thousand years ago small pieces of pinewood dipped in sulphur were used as matches in ancient Egypt. The modern safet
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METHODS TO CONTROL FIRE You must have seen or heard of fire breaking out in homes, shops and factories. If you have seen such an accident, write a short description in your note book. Also, share t
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RAPID, SPONTANEOUS COMBUSTION AND EXPLOSION Bring a burning matchstick or a gas lighter near a gas stove in the kitchen. Turn on the knob of the gas stove. What do you observe? CAUTION : Do not
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WHAT IS FLAME? Observe an LPG flame. Can you tell the colour of the flame. What is the colour of a candle flame? Recall your experience of burning a magnesium ribbon in Class VII. If you do not
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STRUCTURE OF A FLAME Activity 6.5: * Light a candle (Caution : Be careful). * Hold a 4-5 cm long thin glass tube with a pair of tongs and introduce its one end in the
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WHAT IS A FUEL? Recall that the sources of heat energy for domestic and industrial purposes are mainly wood, charcoal, petrol, kerosene etc. These substances are called fuels. A good fuel
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FUEL EFFICIENCY Suppose you were asked to boil a given quantity of water using cow dung, coal and LPG as fuel. Which fuel would you prefer? Give your reason. You may take the help of your parents.
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TYPES OF FUELS Primary (natural) Secondary (artificial) Solid fuels wood, coal, peat, dung, etc.
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RELEASE OF POLLUTANTS AND POISONOUS GASES The increasing fuel consumption has harmful effects on the environment. 1. Carbon fuels like wood, coal, petroleum release unburnt carbon par
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GLOBAL WARMING Combustion of most fuels releases carbon dioxide in the environment. Increased concentration of carbon dioxide in the air is believed to cause global warming. Global war
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ACID RAINS Burning of coal and diesel releases sulphur dioxide gas. It is an extremely suffocating and corrosive gas. Moreover, petrol engines give off gaseous oxides of nitrogen. Oxides of sulphur
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INTRODUCTION TO CLASSIFICATION Have you ever thought of the multitude of life-forms that surround us? Each organism is different from the other to a lesser or greater extent. For instance
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BASIS OF CLASSIFICATION Attempts at classifying living things into groups have been made since time immemorial. Greek thinker Aristotle classified animals according to whether they lived on
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CLASSIFICATION VS EVOLUTION All living things are identified and categorised on the basis of their body design in form and function. Some characteristics are likely to make more wide-ranging chan
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WHITTAKER CLASSIFICATION Biologists, such as Ernst Haeckel (1894), Robert Whittaker (1969), and Carl Woese (1977) have tried to classify all living organisms into broad categories, called ki
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MONERA These organisms do not have a defined nucleus or organelles, nor do any of them show multi-cellular body designs. On the other hand, they show diversity based on many other characteristics
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PROTISTA This group includes many kinds of unicellular eukaryotic organisms. Some of these organisms use appendages, such as hair-like cilia or whip-like flagella for moving around. Their mode
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FUNGI These are heterotrophic eukaryotic organisms. Some of them use decaying organic material as food and are therefore called saprotrophs. Others require a living protoplasm of a host or
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PLANTAE These are multicellular eukaryotes with cell walls. They are autotrophs and use chlorophyll for photosynthesis. Thus, all plants are included in this group. Since plants and animals are the
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ANIMALIA These include all organisms which are multicellular eukaryotes without cell walls. They are heterotrophs. Again, we will look at their subgroups given below. 1. Porifera 2.
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THALLOPHYTA, BRYOPHYTA AND PTERIDOPHYTA The first level of classification among plants depends on whether the plant body has well-differentiated, distinct parts. The next level of classificati
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GYMNOSPERMS AND ANGIOSPERMS Gymnosperms This term is derived from two Greek words: gymno– means naked and sperma– means seed. The plants of this group bear naked seeds and are usuall
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PORIFERA These are organisms which are eukaryotic, multicellular, and heterotrophic. Their cells do not have cell walls. Most animals are mobile. They are further classified based on the exten
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COELENTERATA These are animals living in the water. They show more body design differentiation. There is a cavity in the body. The body is made of two layers of cells: one makes up cells
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PLATYHELMINTHES The body of animals in this group is far more complexly designed than in the two other groups we have considered so far. The body is bilaterally symmetrical, meaning that the left a
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NEMATODA The nematode body is also bilaterally symmetrical and triploblastic. However, the body is cylindrical rather than flattened. There are tissues, but no real organs, although a sort of body
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ANNELIDA Annelid animals are also bilaterally symmetrical and triploblastic, but in addition, they have a true body cavity. This allows true organs to be packaged in the body structure. T
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ARTHROPODA This is probably the largest group of animals. These animals are bilaterally symmetrical and segmented. There is an open circulatory system, and so the blood does not flow in well- defin
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MOLLUSCA In the animals of this group, there is bilateral symmetry. The coelomic cavity is reduced. There is little segmentation. They have an open circulatory system and kidney-like organs for exc
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ECHINODERMATA In Greek, echinos means hedgehog (spiny mammal), and derma means skin. Thus, these are spiny skinned organisms. These are exclusively free-living marine animals. They are triploblasti
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PROTOCHORDATA These animals are bilaterally symmetrical, triploblastic and have a coelom. In addition, they show a new feature of body design, namely a notochord, at least at some stages during the
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VERTEBRATA – CYCLOSTOMATA These animals have a true vertebral column and internal skeleton, allowing a completely different distribution of muscle attachment points to be used for movement.
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VERTEBRATA - PISCES These are fish. They are exclusively aquatic animals. Their skin is covered with scales/ plates. They obtain oxygen dissolved in water by using gills. The body is streamlined, a
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VERTEBRATA - AMPHIBIA These animals differ from the fish in the lack of scales, in having mucus glands in the skin, and a three-chambered heart. Respiration is through either gills or lungs. They l
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VERTEBRATA - REPTILIA These animals are cold-blooded, have scales and breathe through lungs. While most of them have a three-chambered heart, crocodiles have four heart chambers. They lay eggs with
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VERTEBRATA - AVES These are warm-blooded animals and have a four-chambered heart. They lay eggs. There is an outside covering of feathers, and two forelimbs are modified for flight. They breathe th
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VERTEBRATA -MAMMALIA Mammals are warm-blooded animals with four-chambered hearts. They have mammary glands for the production of milk to nourish their young. Their skin has hairs as well as sweat a
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NOMENCLATURE Why is there a need for the systematic naming of living organisms? Activity 7.3: Find out the names of the following animals and plants in as many languages as you can:
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ARE PLANTS AND ANIMALS MADE OF SAME TYPES OF TISSUES? From the last chapter, we recall that all living organisms are made of cells. In unicellular organisms, a single cell performs all basic functi
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MERISTEMATIC TISSUE Activity 6.1: * Take two glass jars and fill them with water. * Now, take two onion bulbs and place one on each jar, as shown in Fig. 6.1.
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PERMANENT TISSUE – SIMPLE PERMANENT TISSUE What happens to the cells formed by meristematic tissue? They take up a specific role and lose the ability to divide. As a result, they form a perma
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PERMANENT TISSUE – COMPLEX PERMANENT TISSUE The different types of tissues we have discussed until now are all made of one type of cell, which looks like each other. Such tissues are called s
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WHAT ARE ANIMAL TISSUES? When we breathe we can actually feel the movement of our chest. How do these body parts move? For this we have specialised cells called muscle cells (Fig. 6.8). The contrac
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EPITHELIAL TISSUE The covering or protective tissues in the animal body are epithelial tissues. Epithelium covers most organs and cavities within the body. It also forms a barrier to keep different
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CONNECTIVE TISSUE Blood is a type of connective tissue. Why would it be called ‘connective’ tissue? A clue is provided in the introduction of this chapter! Now, let us look at this type
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MUSCULAR TISSUE Muscular tissue consists of elongated cells, also called muscle fibres. This tissue is responsible for movement in our body. Muscles contain special proteins called contractile
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NERVOUS TISSUE All cells possess the ability to respond to stimuli. However, cells of the nervous tissue are highly specialised for being stimulated and then transmitting the stimulus very rap
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CELL AND ITS STRUCTURE Cell History While examining a thin slice of cork, Robert Hooke saw that the cork resembled the structure of a honeycomb consisting of many little compartments. Cork is a
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PLASMA MEMBRANE OR CELL MEMBRANE We saw above that the cell has special components called organelles. How is a cell organised? If we study a cell under a microscope, we would come across three f
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CELL WALL Plant cells, in addition to the plasma membrane, have another rigid outer covering called the cell wall. The cell wall lies outside the plasma membrane. The plant cell wall is mainly comp
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NUCLEUS Remember the temporary mount of onion peel we prepared? We had put iodine solution on the peel. Why? What would we see if we tried observing the peel without putting the iodine solution? Tr
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CYTOPLASM When we look at the temporary mounts of onion peel as well as human cheek cells, we can see a large region of each cell enclosed by the cell membrane. This region takes up very little sta
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WHAT ARE CELL ORGANELLES? Every cell has a membrane around it to keep its own contents separate from the external environment. Large and complex cells, including cells from multicellular organisms,
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ENDOPLASMIC RETICULUM The endoplasmic reticulum (ER) is a large network of membrane-bound tubes and sheets. It looks like long tubules or round or oblong bags (vesicles). The ER membrane is similar
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GOLGI APPARATUS The Golgi apparatus, first described by Camillo Golgi, consists of a system of membrane-bound vesicles (flattened sacs) arranged approximately parallel to each other in stacks calle
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LYSOSOMES Structurally, lysosomes are membrane-bound sacs filled with digestive enzymes. These enzymes are made by RER. L ysosomes are a kind of waste disposal system of the cell. These help to kee
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MITOCHONDRIA Mitochondria are known as the powerhouses of the cell. Mitochondria have two membrane coverings. The outer membrane is porous while the inner membrane is deeply folded. These folds inc
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PLASTIDS AND VACUOLES Plastids Plastids are present only in plant cells. There are two types of plastids – chromoplasts (coloured plastids) and leucoplasts (white or colourless plastids).&
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MITOSIS AND MEIOSIS Each cell thus acquires its structure and ability to function because of the organisation of its membrane and organelles in specific ways. The cell thus has a basic structural o
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INTRODUCTION Activity 13.1: * We have all heard of the earthquakes in Latur, Bhuj, Kashmir etc. or the cyclones that lashed the coastal regions. Think of as many different ways as po
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THE SIGNIFICANCE OF HEALTH We have heard the word ‘health’ used quite frequently. We use it ourselves as well, when we say things like ‘my grandmother’s health is not good&r
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PERSONAL AND COMMUNITY ISSUES BOTH MATTER FOR HEALTH If health means a state of physical, mental and social well-being, it cannot be something that each one of us can achieve entirely on our o
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DISTINCTION BETWEEN HEALTHY AND DISEASE FREE If this is what we mean by ‘health’, what do we mean by ‘disease’? The word is actually self-explanatory – we ca
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WHAT DOES DISEASE LOOK LIKE? Let us now think a little more about diseases. In the first place, how do we know that there is a disease? In other words, how do we know that there is something wrong
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ACUTE AND CHRONIC DISEASES The manifestations of the disease will be different depending on a number of factors. Some diseases last for only very short periods of time, and these are called acute d
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CHRONIC DISEASES AND POOR HEALTH Acute and chronic diseases have different effects on our health. Any disease that causes poor functioning of some part of the body will affect our health. This is b
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CAUSES OF DISEASES What causes disease? When we think about the causes of diseases, we must remember that there are many levels of such causes. Let us look at an example. If there is a baby sufferi
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INFECTIOUS AND NON INFECTIOUS CAUSES As we have seen, it is important to keep public health and community health factors in mind when we think about the causes of diseases. We can take that approac
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INFECTIOUS AGENTS We have seen that the entire diversity seen in the living world can be classified into a few groups. This classification is based on common characteristics between different organ
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MEANS OF SPREAD How do infectious diseases spread? Many microbial agents can commonly move from an affected person to someone else in a variety of ways. In other words, they can be ‘communica
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ORGAN AND TISSUE SPECIFIC MANIFESTATIONS The disease-causing microbes enter the body through these different means. Where do they go then? The body is very large when compared to the microbes. So t
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PRINCIPLES OF TREATMENT What are the steps taken by your family when you fall sick? Have you ever thought why you sometimes feel better if you sleep for some time? When does the treatment involve m
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PRINCIPLES OF PREVENTION All of what we have talked about so far deals with how to get rid of an infection in someone who has the disease. But there are three limitations to this approach to dealin
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RESOURCES ON THE EARTH Our planet, Earth is the only one on which life, as we know it, exists. Life on Earth is dependent on many factors. Most life-forms we know need an ambient temperature, water
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COMPOSITION OF AIR We have already talked about the composition of air in the first chapter. It is a mixture of many gases like nitrogen, oxygen, carbon dioxide and water vapour. It is interesting
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THE ROLE OF THE ATMOSPHERE IN CLIMATE CONTROL We have talked of the atmosphere covering the Earth, like a blanket. We know that air is a bad conductor of heat. The atmosphere keeps the average temp
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THE MOVEMENT OF AIR: WINDS We have all felt the relief brought by cool evening breezes after a hot day. And sometimes, we are lucky enough to get rains after some days of really hot weather. What c
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RAIN Let us go back now to the question of how clouds are formed and bring us rain. We could start by doing a simple experiment which demonstrates some of the factors influencing these climatic cha
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AIR POLLUTION We keep hearing of the increasing levels of oxides of nitrogen and sulphur in the news. People often bemoan the fact that the quality of air has gone down since their childhood. How i
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EXISTENCE OF WATER AND ITS NECESSITY Water occupies a very large area of the Earth’s surface and is also found underground. Some amount of water exists in the form of water vapour in the atmo
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WATER POLLUTION Water dissolves the fertilisers and pesticides that we use on our farms. So some percentage of these substances are washed into the water bodies. Sewage from our towns and cities an
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FACTORS AND PROCESSES THAT MAKE SOIL Soil is an important resource that decides the diversity of life in an area. But what is the soil and how is it formed? The outermost layer of our Earth is call
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THE WATER CYCLE A constant interaction between the biotic and abiotic components of the biosphere makes it a dynamic, but stable system. These interactions consist of a transfer of matter and energ
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THE NITROGEN CYCLE Nitrogen gas makes up 78% of our atmosphere and nitrogen is also a part of many molecules essential to life like proteins, nucleic acids (DNA and RNA) and some vitamins. Nitrogen
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THE CARBON CYCLE Carbon is found in various forms on the Earth. It occurs in the elemental form as diamonds and graphite. In the combined state, it is found as carbon dioxide in the atmosphere, as
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THE GREENHOUSE EFFECT Recall the reading taken by you under (iii) in Activity 14.1. Activity 14.1. Measure the temperature of the following : Take (i) a beaker full of water, (i
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THE OXYGEN CYCLE Oxygen is a very abundant element on our Earth. It is found in the elemental form in the atmosphere to the extent of 21%. It also occurs extensively in the combined form in the Ear
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OZONE LAYER - FORMATION, USES AND HARMFUL EFFECTS Elemental oxygen is normally found in the form of a diatomic molecule. However, in the upper reaches of the atmosphere, a molecule containing three
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MACAVITY: THE MYSTERY CAT - T.S. ELIOT (Poet) Before you read Do you have a pet cat? Have you ever noticed anything mysterious about it? It is not easy to say whether every cat is a mystery, but
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INTRODUCTION We know that all living organisms need food. Food supplies proteins, carbohydrates, fats, vitamins and minerals, all of which we require for body development, growth, and health. Both
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TYPES OF CROP YIELDS Cereals such as wheat, rice, maize, millets, and sorghum provide us carbohydrates for energy requirements. Pulses like gram (chana), pea (matar), black gram (urad), green gram
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CROP VARIETY IMPROVEMENT This approach depends on finding a crop variety that can give a good yield. Varieties or strains of crops can be selected by breeding for various useful characteristics suc
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NUTRIENT MANAGEMENT In India, as in many other agriculture-based countries, farming ranges from small to very large farms. Different farmers thus have more or less land, money, and access to inform
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MANURE Manure contains large quantities of organic matter and also supplies small quantities of nutrients to the soil. Manure is prepared by the decomposition of animal excreta and plant waste. Man
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FERTILIZERS Fertilizers are commercially produced plant nutrients. Fertilizers supply nitrogen, phosphorus, and potassium. They are used to ensure good vegetative growth (leaves, branches, and flow
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IRRIGATION Most agriculture in India is rain-fed, that is, the success of crops in most areas is dependent on timely monsoons and sufficient rainfall spread through most of the growing season. Henc
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CROPPING PATTERNS Different ways of growing crops can be used to give maximum benefit. Mixed cropping is growing two or more crops simultaneously on the same piece of land, for example, wheat +
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STORAGE OF GRAINS Field crops are infested by a large number of weeds, insect pests and diseases. If weeds and pests are not controlled at the appropriate time then they can damage the crops so muc
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CATTLE FARMING Animal husbandry is the scientific management of animal livestock. It includes various aspects such as feeding, breeding and disease control. Animal-based farming includes cattle, go
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POULTRY FARMING Poultry farming is undertaken to raise domestic fowl for egg production and chicken meat. Therefore, improved poultry breeds are developed and farmed to produce layers for eggs
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EGG AND BROILER PRODUCTION Broiler chickens are fed with vitamin-rich supplementary feed for good growth rate and better feed efficiency. Care is taken to avoid mortality and to maintain feathering
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FISH PRODUCTION - MARINE FISHERIES Fish is a cheap source of animal protein for our food. Fish production includes the finned true fish as well as shellfish such as prawns and molluscs. There
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FISH PRODUCTION - INLAND FISHERIES Fresh water resources include canals, ponds, reservoirs and rivers. Brackish water resources, where seawater and fresh water mix together, such as estu
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BEE-KEEPING Honey is widely used and therefore bee- keeping for making honey has become an agricultural enterprise. Since bee-keeping needs low investments, farmers use it as an additional income g
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REST AND MOTION In everyday life, we see some objects at rest and others in motion. Birds fly, fish swim, blood flows through veins and arteries, and cars move. Atoms, molecules, planets, stars,&nb
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MOTION ALONG A STRAIGHT LINE We describe the location of an object by specifying a reference point. Let us understand this by an example. Let us assume that a school in a village is 2 km north of t
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UNIFORM MOTION AND NON-UNIFORM MOTION Consider an object moving along a straight line. Let it travel 5 m in the first second,5 m more in the next second, 5 m in the third second, and 5 m in the fou
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SPEED WITH DIRECTION Figure 8.2(a): Figure 8.2(b): Look at the situations given in Fig. 8.2. If the bowling speed is 143 kmh–1 in Fig. 8.2(a) what does it mean? What do you unde
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ACCELERATION During the uniform motion of an object along a straight line, the velocity remains constant with time. In this case, the change in velocity of the object for any time interval is zero.
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DISTANCE-TIME GRAPHS Graphs provide a convenient method to present basic information about a variety of events. For example, in the telecast of a one-day cricket match, vertical bar graphs show the
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VELOCITY-TIME GRAPHS Velocity-Time graph for object moving with uniform velocity The variation in velocity with time for an object moving in a straight line can be represented by a velocity-time
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INTRODUCTION TO EQUATIONS OF MOTION When an object moves along a straight line with uniform acceleration, it is possible to relate its velocity, acceleration during motion, and the distance covered
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EQUATION FOR POSITION-TIME RELATION Let us consider that the object has travelled a distance s in time t under uniform acceleration a. In Fig. 8.8, the distance travelled by the object is obtained
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EQUATION FOR POSITION-VELOCITY RELATION From the velocity-time graph shown in Fig. 8.8, the distance s travelled by the object in time t, moving under uniform acceleration a is given by the area en
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UNIFORM CIRCULAR MOTION When the velocity of an object changes, we say that the object is accelerating. The change in the velocity could be due to change in its magnitude or the direction of the mo
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WHAT IS FORCE? In the previous chapter, we described the motion of an object along a straight line in terms of its position, velocity, and acceleration. We saw that such a motion can be uniform or
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BALANCED AND UNBALANCED FORCES Fig. 9.3 shows a wooden block on a horizontal table. Two strings X and Y are tied to the two opposite faces of the block as shown. If we apply a force by pulling the
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GALILEO AND NEWTON RESEARCH By observing the motion of objects on an inclined plane Galileo deduced that objects move with a constant speed when no force acts on them. He observed that when a marbl
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LAW OF INERTIA The first law of motion is stated as: An object remains in a state of rest or of uniform motion in a straight line unless compelled to change that state by an applied force. &n
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INERTIA AND MASS All the examples and activities are given so far illustrate that there is a resistance offered by an object to change its state of motion. If it is at rest it tends to remain at re
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SECOND LAW OF MOTION The first law of motion indicates that when an unbalanced external force acts on an object, its velocity changes, that is, the object gets an acceleration. We would now li
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MATHEMATICAL FORMULATION OF SECOND LAW Suppose an object of mass, m is moving along a straight line with an initial velocity, u. It is uniformly accelerated to velocity, v in time, t by t
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EXPLANATION OF THIRD LAW OF MOTION The first two laws of motion tell us how an applied force changes the motion and provide us with a method of determining the force. The third law of mot
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EXPLANATION OF CONSERVATION OF MOMENTUM Suppose two objects (two balls A and B, say) of masses mA and mB are travelling in the same direction along a straight line at different velocities
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THE LAST BARGAIN - RABINDRANATH TAGORE (Poet) Before you read A bargain is an agreement in which both parties promise to do something for each other. Someone is looking for work, waiting to be h
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THE SCHOOL BOY - WILLIAM BLAKE (Poet) Before you read The schoolboy in the poem is not a happy child. What mak him unhappy? Why does he compare himself to a bird that liv in a cage, or a plant t
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WHEN I SET OUT FOR LYONNESSE - THOMAS HARDY (Poet) Before you read As a young apprentice architect, British poet and novelist Thomas Hardy once visited a parish to supervise the restoration of a
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ON THE GRASSHOPPER AND CRICKET - JOHN KEATS (Poet) Before you read Unlike The Ant and the Cricket, which tells a story, this is a nature poem. In it, the grasshopper and cricket do not appear as
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INTRODUCTION In Chapters 8 and 9, we have learnt about the motion of objects and force as the cause of motion. We have learnt that a force is needed to change the speed or the direction of motion o
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WHAT IS GRAVITATION? We know that the moon goes around the earth. An object when thrown upwards, reaches a certain height and then falls downwards. It is said that when Newton was sitting under a t
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UNIVERSAL LAW OF GRAVITATION Every object in the universe attracts every other object with a force which is proportional to the product of their masses and inversely proportional to the square of t
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IMPORTANCE OF UNIVERSAL LAW OF GRAVITATION The universal law of gravitation successfully explained several phenomena which were believed to be unconnected: i. the force that binds us
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Acceleration due to Gravity (G) Let us try to understand the meaning of free fall by performing this activity. Activity 10.2: ( throwing a stone upward ) * Take a s
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CALCULATING VALUE OF “G” To calculate the value of g, we should put the values of G, M, and R in Eq. (10.9), namely, universal gravitational constant, G = 6.7\(\times\) 10&nda
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MOTION OF OBJECTS UNDER THE INFLUENCE OF GRAVITATIONAL FORCE OF THE EARTH Let us do an activity to understand whether all objects hollow or solid, big or small, will fall from a height at the
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MASS AND WEIGHT Mass We have learnt in the previous chapter that the mass of an object is the measure of its inertia (section 9.3). We have also learnt that greater the mass, the greater is the
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WEIGHT OF AN OBJECT ON THE MOON We have learnt that the weight of an object on the earth is the force with which the earth attracts the object. In the same way, the weight of an object on
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EXPLANATION OF THRUST AND PRESSURE Have you ever wondered why a camel can run in a desert easily? Why an army tank weighing more than a thousand tonne rests upon a continuous chain? Why a truck or
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PRESSURE IN FLUIDS All liquids and gases are fluids. A solid exerts pressure on a surface due to its weight. Similarly, fluids have weight, and they also exert pressure on the base and walls o
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BUOYANCY Have you ever had a swim in a pool and felt lighter? Have you ever drawn water from a well and felt that the bucket of water is heavier when it is out of the water? Have you ever wondered
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WHY OBJECTS FLOAT OR SINK WHEN PLACED ON THE SURFACE OF WATER? Let us do the following activities to arrive at an answer for the above question. Activity 10.5: * Take a b
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EXPLANATION OF ARCHIMEDES’ PRINCIPLE Activity 10.7: * Take a piece of stone and tie it to one end of a rubber string or a spring balance. * Suspend the stone by
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EXPLANATION OF RELATIVE DENSITY As you know, the density of a substance is defined as the mass of a unit volume. The unit of density is kilogram per meter cube (kgm–3). The density of a given
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INTRODUCTION In the previous few chapters, we have talked about ways of describing the motion of objects, the cause of motion, and gravitation. Another concept that helps us understand and int
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NOT MUCH ‘WORK’ IN SPITE OF WORKING HARD! What is work? There is a difference in the way we use the term ‘work’ in day-to-day life and the way we use it in science. To make
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SCIENTIFIC CONCEPTION OF WORK To understand the way we view work and define work from the point of view of science, let us consider some situations: Push a pebble lying on a surface. The pebble
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WORK DONE BY A CONSTANT FORCE How is work defined in science? To understand this, we shall first consider the case when the force is acting in the direction of displacement. Let a cons
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WHAT IS ENERGY? Life is impossible without energy. The demand for energy is ever-increasing. Where do we get energy from? The Sun is the biggest natural source of energy to us. Many of our energy s
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FORMS OF ENERGY – KINETIC ENERGY Luckily the world we live in provides energy in many different forms. The various forms include mechanical energy (potential energy + kinetic energy), he
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FORMS OF ENERGY – POTENTIAL ENERGY Activity 11.8: * Take a rubber band. * Hold it at one end and pull from the other. The band stretches. * Release t
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POTENTIAL ENERGY OF AN OBJECT AT A HEIGHT An object increases its energy when raised through a height. This is because work is done on it against gravity while it is being raised. The energy presen
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ARE VARIOUS ENERGY FORMS INTERCONVERTIBLE? Can we convert energy from one form to another? We find in nature a number of instances of conversion of energy from one form to another Acti
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LAW OF CONSERVATION OF ENERGY Activity 11.13: * Sit in small groups. * Discuss the various ways of energy conversion in nature. * Discuss following questio
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WHAT IS MEANT BY RATE OF DOING WORK? Do all of us work at the same rate? Do machines consume or transfer energy at the same rate? Agents that transfer energy do work at different rates. Let us unde
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COMMERCIAL UNIT OF ENERGY The unit joule is too small and hence is inconvenient to express large quantities of energy. We use a bigger unit of energy called kilowatt hour (kW h). What
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INTRODUCTION Everyday we hear sounds from various sources like humans, birds, bells, machines, vehicles, televisions, radios etc. Sound is a form of energy which produces a sensation of hearing in
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HOW IS SOUND PRODUCED? Activity 12.1: ( vibration of tuning fork ) * Take a tuning fork and set it vibrating by striking its prong on a rubber pad. Bring it near your ear. *  
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HOW SOUND IS PROPAGATED? Sound is produced by vibrating objects. The matter or substance through which sound is transmitted is called a medium. It can be solid, liquid or gas. Sound moves through a
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SOUND NEEDS A MEDIUM TO TRAVEL Sound is a mechanical wave and needs a material medium like air, water, steel etc. for its propagation. It cannot travel through vacuum, which can be demonstrated by
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SOUNDWAVES ARE LONGITUDINAL WAVES Activity 12.4: * Take a slinky. Ask your friend to hold one end. You hold the other end. * Now stretch the slinky as shown in Fig. 12.7 (a). Then
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CHARACTERISTICS OF A SOUND WAVE We can describe a sound wave by its * Density/pressure * Wavelength and * speed Characteristics of sou
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SPEED OF SOUND IN DIFFERENT MEDIA Sound propagates through a medium at a finite speed. The sound of a thunder is heard a little later than the flash of light is seen. So, we can make o
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ECHO Sound bounces off a solid or a liquid like a rubber ball bounces off a wall. Like light, sound gets reflected at the surface of a solid or liquid and follows the same laws of reflection as you
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REVERBERATION A sound created in a big hall will persist by repeated reflection from the walls until it is reduced to a value where it is no longer audible. The repeated reflection that results in
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USES OF MULTIPLE REFLECTION OF SOUND 1. Megaphones or loudhailers, horns, musical instruments such as trumpets and shehanais, are all designed to send sound in a particular direction without
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AUDIBLE RANGE OF SOUND The audible range of sound for human beings extends from about 20 Hz to 20000 Hz (one Hz = one cycle/s). Children under the age of five and some animals, such as dogs ca
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DIFFERENT APPLICATIONS OF ULTRASOUND Ultrasounds are high-frequency waves. Ultrasounds are able to travel along well-defined paths even in the presence of obstacles. Ultrasounds are used extensivel
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SONAR The acronym SONAR stands for SOund Navigation And Ranging. Sonar is a device that uses ultrasonic waves to measure the distance, direction, and speed of underwater objects. How does the sonar
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HUMAN EAR AND ITS STRUCTURE How do we hear? We are able to hear with the help of an extremely sensitive device called the ear. It allows us to convert pressure variations in the air with audible f
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THE SQUIRREL - MILDRED BOWERS ARMSTRONG (Poet) Before you read You may have seen a squirrel sitting on the ground eating a nut. What did it look like? Here is a poet’s description of just
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WHAT IS FORCE? In Class VII, you have learned how objects move. Do you recall how we can decide whether an object is moving faster than the other? What does the distance move by an object in unit t
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FORCE – A PUSH OR A PULL Actions like picking, opening, shutting, kicking, hitting, lifting, flicking, pushing, pulling are often used to describe certain tasks. Each of these actions usually
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HOW FORCES ACT DUE TO AN INTERACTION? Suppose a man is standing behind a stationary car [Fig.11.2(a)]. Will the car move due to his presence? Suppose the man now begins to push the car [Fig.11.2(b)
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MORE ABOUT FORCES Let us try to learn more about forces. Activity 11.2: ( Pushing a box or table ) * Choose a heavy object like a table or a box, which you can move only
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EFFECT OF FORCE ON STATE OF MOTION Let us now find out what happens when a force acts on an object. Effect of force on an object Force moves the object at rest It increases or
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EFFECT OF FORCE ON SHAPE OF AN OBJECT Activity 11.5: * Some situations have been given in Column 1 of Table 11.2 in which objects are not free to move. Column 2 of the Table sugg
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MUSCULAR FORCE Can you push or lift a book lying on a table without touching it? Can you lift a bucket of water without holding it? Generally, to apply a force on an object, your body has to be in
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FRICTION Recall some of your experiences. A ball rolling along the ground gradually slows down and finally comes to rest. When we stop pedalling a bicycle, it gradually slows down and finally comes
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MAGNETIC FORCE Activity 11.6: ( Observing magnetic force ) * Take a pair of bar magnets. * Place the longer side of one of the magnets over three round shaped pe
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ELECTROSTATIC FORCE Activity 11.7: ( observing electrostatic force ) * Take a plastic straw and cut it into nearly two equal pieces. * Suspend one of the pieces from
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GRAVITATIONAL FORCE You know that a coin or a pen falls to the ground when it slips off your hand. Leaves and fruits also fall to the ground when they get detached from the plant. Have you ever won
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WHAT IS PRESSURE? You have learned in Class VII that strong winds during a storm or a cyclone can blow away even the roof-tops. You also learned that winds and cyclones are caused by differences in
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HOW PRESSURE IS EXERTED BY LIQUID AND GASES? Activity 11.8: ( pressure depends height of water ) * Take a transparent glass tube or a plastic pipe. The length of the pipe/ tube shoul
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WHAT IS ATMOSPHERIC PRESSURE? You know that there is air all around us. This envelop of air is known as the atmosphere. The atmospheric air extends up to many kilometers above the surface of t
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WHAT IS FRICTION? REAL-LIFE EXAMPLES OF FRICTION You might have seen a driver of a car or a truck slowing down the vehicle at a traffic signal. You, too slow down your bicycl
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FORCE OF FRICTION Activity 12.1: * Gently push a book on a table [Fig. 12.2(a)]. * You observe that it stops after moving for some distance. * Repeat
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FACTORS AFFECTING FRICTION Activity 12.2: * Tie a string around a brick. Pull the brick by a spring balance (Fig. 12.3). * You need to apply some force. Note down the
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WHY FRICTION IS NECESSARY? Recall now some of your experiences. Is it easier to hold a kulhar (earthen pot) or a glass tumbler? Suppose the outer surface of the tumbler is greasy or has a thin laye
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HOW FRICTION IS INCREASED OR DECREASED? As you have seen in the previous section, friction is desirable in some situations. Have you ever thought why the sole of your shoe is grooved [Fig. 12.11
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WHEELS REDUCE FRICTION You must have seen attaches and other pieces of luggage fitted with rollers. Even a child can pull such pieces of luggage (Fig. 12.14). Why is it so? Let us find out. &nbs
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FLUID FRICTION You know that air is very light and thin. Yet it exerts a frictional force on objects moving through it. Similarly, water and other liquids exert a force of friction when objects mov
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Before you read Have you ever read a comic book? A comic book contains stories told mainly through pictures. STORY – GOPAL AND THE HILSA FISH
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Before you read This is a story about an honest and hardworking old couple and their pet dog. The neighbours are troublesome, and the dog dies a sad death. The spirit of the dog gives solace and su
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Before you read Can a shoemaker be called an artist? Yes, if he has the same skill and pride in his trade as any other artist and the same respect for it too. Mr. Gessler, a German shoemaker settle
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Before you read Nishad, a boy of seven (also called Seven because his name means the seventh note on the musical scale) and his ten-year-old sister Maya are very curious about one Mr Nath. Then one
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Before you read This story is taken from Charlie and the Great Glass Elevator. Mr. Willy Wonka begins by inventing Wonka- Vite, which makes people younger. But Wonka- Vite is too stron
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Before you read Fire is both useful and dangerous. What is fire? How did we discover it? How do we control it? STORY – FIRE: FRIEND AND FOE Part I Early man didn’t know what fi
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Before you read If you wish to go on a long bicycle ride, the bicycle should be in good condition. If possible, an expert mechanic should overhaul it. But what happens if the machine has a will of
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Before you read Sport is an integral part of a healthy life. It is one way in which we amuse ourselves, compete with each other and stay fit. Among the various sports such as hockey, football and t
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THE REBEL - D. J. ENRIGHT (Poet) Before you read Do you know anyone who always disagrees with you or your friends, or likes to do the opposite of what everyone thinks they should do? Think of a
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THE SHED - FRANK FLYNN (Poet) Before you read Do you know what a shed is? A cowshed, a tool shed a woodshed, for example. It’s a small room, away from the main house, for storing or k
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CHIVVY - MICHAEL ROSEN (Poet) Before you read Ask yourself as well as your partner: Do you like to be always told what to do or not to do? Do grown-ups do this, in your experienc
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TREES - SHIRLEY BAUER (Poet) Before you read Take a few minutes to tell one another the names of trees that you know or have heard of. Mention the things trees give us. Then read this poem about
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MYSTERY OF THE TALKING FAN - MAUDE RUBIN (Poet) Before you read Is there a ceiling fan in the room where you are sitting now? Is the fan quiet or noisy? If it is noisy, you may be sure it is a d
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DAD AND THE CAT AND THE TREE - KIT WRIGHT (Poet) ( Story Video ) Before you read Have you ever seen a cat climbing a tree? Sometimes a cat may climb too high and get stuck in the tree. The po
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MEADOW SURPRISES - LOIS BRANDT PHILLIPS (Poet) Before you read Walk across a green field, a park, or even under a clump of trees, and you will notice many wonderful things. What are some of the
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GARDEN SNAKE - MURIEL L. SONNE (Poet) Before you read Have you ever seen a snake fighting a mongoose, or getting into a hole, or swimming in the river? Everyone, almost everyone, believes that s
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Before you read Activity: Do you like homework? Do you do it yourself, or do you get help? What homework do you usually have? STORY – WHO DID PATRICK’S HOMEWORK? – CAROL MOO
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Before you read You may know that the dog and the wolf are closely related. You may also know something about how over the centuries, human beings have domesticated and tamed wild animals. Here is
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DEFORESTATION AND ITS CAUSES We saw in Class VII that Paheli and Boojho had visited the forest along with Professor Ahmad and Tibu. They were eager to share their experiences with their classm
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CONSEQUENCES OF DEFORESTATION Paheli and Boojho recalled the consequences of deforestation. They remembered that deforestation increases the temperature and pollution level on the earth.
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HOW CAN WE CONSERVE FORESTS AND WILDLIFE? Having become aware of the effects of deforestation, Paheli and Boojho are worried. They go to Professor Ahmad and ask him how forests and wildlife can be
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BIOSPHERE RESERVE Children along with Professor Ahmad and Madhavji enter the biosphere reserve area. Madhavji explains that biosphere reserves are the areas meant for the conservation of biodiversi
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WHAT IS FLORA AND FAUNA? As the children walk around the biosphere reserve they appreciate the green wealth of the forest. They are very happy to see tall teak trees and animals inside the for
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WHAT ARE ENDEMIC SPECIES? Soon the group quietly enters the deep forest. Children are surprised to see a very big squirrel. This squirrel has a big fluffy tail. They are very curious to know about
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WILDLIFE SANCTUARY Soon Paheli sees a board with " Pachmarhi Wildlife Sanctuary " written on it. Professor Ahmad explains that killing (poaching) or capturing animals, i
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NATIONAL PARKS On the roadside, there was another board on which was written " Satpura National Park ". Children are now eager to go there. Madhavji tells them that thes
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RED DATA BOOK Professor Ahmad explains about Red Data Book to the children. He tells them that Red Data Book is the sourcebook that keeps a record of all the endangered animals and plants
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MIGRATION The excursion party then enters deeper into the forest under the guidance of Madhavji. They sit near the Tawa. Reservoir to relax for some time. Paheli observes some of
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SAVE PAPER – SAVE TREES Professor Ahmad draws the attention of the children to another cause of deforestation. He tells them that it takes 17 full-grown trees to make one tonne of paper. Ther
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REFORESTATION – WAY TO LIFE Professor Ahmad suggests that the answer to deforestation is reforestation. Reforestation is the restocking of the destroyed forests by planting new trees. The pla
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INTRODUCTION AND DISCOVERY OF CELL You have already learned that things around us are either living or non-living. Further, you may recall that all living organisms carry out certain basic fun
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THE CELL - BASIC STRUCTURAL UNIT Both, bricks in a building and cells in the living organisms, are basic structural units [Fig. 8.2(a), (b)]. The buildings, though built of similar bricks, have dif
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NUMBER OF CELLS How do scientists observe and study living cells? They use microscopes that magnify objects. Stains (dyes) are used to color parts of the cell to study the detailed structure.
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SHAPE OF CELLS Refer to Fig. 8.3 (a). How do you define the shape of the amoeba in the figure? You may say that the shape appears irregular. In fact, the amoeba has no definite shape, unlike other
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SIZE OF CELLS The size of cells in living organisms may be as small as a millionth of a metre (micrometre or micron) or maybe as large as a few centimetres. However, most of the cells are
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STRUCTURE AND FUNCTION OF CELL You have learned that each living organism has many organs. You have studied in Class VII about the digestive organs which together constitute the digestive system. E
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CELL MEMBRANE The basic components of a cell are (Fig. 8.7). 1. Cell membrane, 2. Cytoplasm and 3. Nucleus Figure 8.7: The cytoplasm and n
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CYTOPLASM AND NUCLEUS Cytoplasm It is the jelly-like substance present between the cell membrane and the nucleus. Various other components, or organelles, of cells are present in the cytoplasm.&
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plant cell vs animal cell If you recall Activities 8.3 and 8.4, Activity 8.3: (Observing onion peel under microscope) * In order to observe the basic components of th
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REPRODUCTION AND ITS MODES Do you recall the processes of digestion, circulation, and respiration which you have studied in your previous classes? These processes are essential for the survival of
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WHAT IS SEXUAL REPRODUCTION Try to recall reproduction in plants which you studied in Class VII. You will remember that plants that reproduce sexually have male and female reproductive parts.
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MALE REPRODUCTIVE ORGANS The male reproductive organs include a pair of testes (singular, testis), two sperm ducts, and a penis (Fig. 9.1). The testes produce the male gametes called sperms. Millio
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FEMALE REPRODUCTIVE ORGANS The female reproductive organs are a pair of ovaries, oviducts (fallopian tubes), and the uterus (Fig. 9.3). The ovary produces female gametes called ova (eggs)
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FERTILISATION The first step in the process of reproduction is the fusion of a sperm and an ovum. When sperms come in contact with an egg, one of the sperms may fuse with the egg. Such fusion of th
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DEVELOPMENT OF EMBRYO Fertilisation results in the formation of zygote which begins to develop into an embryo [Fig.9.8(a)]. The zygote divides repeatedly to give rise to a ball of cells [Fig.9.8(b)
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WHAT ARE VIVIPAROUS AND OVIPAROUS ANIMALS? We have learnt that some animals give birth to young ones while some animals lay eggs which later develop into young ones. The animals which give birth to
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METAMORPHOSIS The new individuals which are born or hatched from the eggs continue to grow till they become adults. In some animals, the young ones may look very different from the adults. Recall t
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BUDDING IN HYDRA So far, we have learnt about reproduction in some familiar animals. But what about very small animals like hydra and microscopic organisms like amoeba? Do you know how they reprodu
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BINARY FISSION IN AMOEBA Another method of asexual reproduction is observed in the microscopic organism, amoeba. Let us see how this happens. You have already learnt about the structur
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WHAT IS MEANT BY ADOLESCENCE AND PUBERTY? In the previous chapter, you have learnt how animals reproduce. It is only after ‘growing up’ to a certain age that human beings and
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INCREASE IN HEIGHT The most conspicuous change during puberty is the sudden increase in height. At this time the long bones, that is, the bones of the arms and the legs elongate and make a person t
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CHANGE IN BODY SHAPE AND VOICE Change in body shape Have you noticed that boys in your class have broader shoulders and wider chests than boys in junior classes? This is because they have enter
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INCREASED ACTIVITY OF SWEAT AND SEBACEOUS GLANDS During puberty the secretion of sweat glands and sebaceous glands (oil glands) increases. Many young people get acne and pimples on the face at
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DEVELOPMENT OF SEX ORGANS Look up Fig. 9.1 and 9.3 which show sex organs of humans. At puberty, male sex organs like the testes and penis develop completely. The testes also begin to produce s
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REACHING MENTAL, INTELLECTUAL AND EMOTIONAL MATURITY Adolescence is also a period of change in a person’s way of thinking. Adolescents are more independent than before and are also self-consc
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EXPLANATION OF SECONDARY SEXUAL CHARACTERS You have learnt in Chapter 9, that testes and ovaries are the reproductive organs. They produce the gametes, that is, sperms and ova. In girls, breasts be
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HORMONES ROLE IN REPRODUCTIVE FUNCTION Endocrine glands release hormones into the bloodstream to reach a particular body part called target site. The target site responds to the hormone. There are
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HUMAN REPRODUCTIVE PHASES Adolescents become capable of reproduction when their testes and ovaries begin to produce gametes. The capacity for maturation and production of gametes lasts for a much l
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HOW IS THE SEX OF THE BABY DETERMINED? Inside the fertilised egg or zygote is the instruction for determining the sex of the baby. This instruction is present in the thread-like structures, called
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THYROXINE, INSULIN, ADRENALIN AND GROWTH HORMONE Look at Fig. 10.3 again. Figure 10.3: The onset of puberty is controlled by hormones The hormones secreted by the pituitary
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INSECT HORMONES You have already learnt about the life history of the silk moth and the frog. The caterpillar has to pass through various stages to become an adult moth. Recall from Class VII the s
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NUTRITIONAL NEEDS OF THE ADOLESCENTS The physical and mental well being of an individual is regarded as an individual’s health. To keep the body healthy, every human being, at any age, needs
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PERSONAL HYGIENE AND PHYSICAL EXERCISE Personal hygiene Everyone should have a bath at least once everyday. It is more necessary for teenagers because the increased activity of sweat glands som
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SAY “NO” TO DRUGS Adolescence is a period of much activity in the body and mind which is a normal part of growing up. So do not feel confused or insecure. If anybody suggests that you w
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PRODUCTION AND DISTRIBUTION OF FOOD Paheli and Boojho went to their uncle’s house during the summer vacation. Their uncle is a farmer. One day they saw some tools like khurpi, sickl
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DIFFERENT KINDS OF CROPS Till 10,000 B.C.E. people were nomadic. They were wandering in groups from place to place in search of food and shelter. They ate raw fruits and vegetables and started hunt
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BASIC PRACTICES OF CROP PRODUCTION Why paddy can not be grown in the winter season? Paddy requires a lot of water. Therefore, it is grown only in the rainy season. Cultivation of crops i
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PREPARATION OF SOIL The preparation of the soil is the first step before growing a crop. One of the most important tasks in agriculture is to turn the soil and loosen it. This allows the roots to p
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AGRICULTURAL IMPLEMENTS- PLOUGH, HOE AND CULTIVATOR Before sowing the seeds, it is necessary to break soil clumps to get better yield. This is done with the help of various tools. The mai
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SELECTION OF SEED AND SOWING Sowing is an important part of crop production. Before sowing, good quality, clean and healthy seeds of a good variety—are selected. Farmers prefer to use seeds w
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ADDING MANURE AND FERTILISERS The substances which are added to the soil in the form of nutrients for the healthy growth of plants are called manure and fertilisers. Soil supplies mine
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CROP ROTATION Another method of replenishing the soil with nutrients is through crop rotation. This can be done by growing different crops alternately. Earlier, farmers in northern India used to gr
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DIFFERENCE BETWEEN A FERTILISER AND MANURE S. No. Fertiliser Manure 1. Fertiliser is a man-made inorganic salt.
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IRRIGATION AND ITS SOURCES All living beings need water to live. Water is important for proper growth and development. Water is absorbed by the plant roots. Along with water, minerals and fertilise
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TRADITIONAL METHODS OF IRRIGATION The water available in wells, lakes and canals is lifted up by different methods in different regions, for taking it to the fields. Cattle or human la
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MODERN METHODS OF IRRIGATION Modern methods of irrigation help us to use water economically. The main methods used are as follows: Sprinkler System This system is more useful on the
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WEEDICIDES Boojho and Paheli went to a nearby wheat field and saw that there were some other plants in the field, growing along with wheat plants. In a field many other undes
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THRESHING AND WINNOWING Harvesting of a crop is an important task. The cutting of crop after it is mature is called harvesting. In harvesting, crops are pulled out or cut close to the ground. It us
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STORAGE Storage of produce is an important task. If the harvested grains are to be kept for longer time, they should be safe from moisture, insects, rats, and microorganisms. Harvested grains have
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FOOD FROM ANIMALS Activity 1.3: Make the following Table in your notebook and complete it. S.No. Food Sources 1.
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ROLE OF ACIDS, BASES AND SALTS IN OUR DAILY LIFE We use in our daily life a large number of substances such as lemon,tamarind,common salt, sugar, and vinegar. Do they have the same
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ACIDS Curd, lemon juice, orange juice and vinegar taste sour. These substances taste sour because they contain acids. The chemical nature of such substances is acidic. The word acid comes from the
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BASES What about baking soda? Does it also taste sour? If not, what is its taste? Since it does not taste sour it means, that it has no acids in it. It is bitter in taste. If you rub its solut
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WHAT IS INDICATOR? If we cannot taste every substance, how do we find its nature? Special type of substances are used to test whether a substance is acidic or basic. These substances a
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NATURAL INDICATOR – LITMUS The most commonly used natural indicator is litmus. It is extracted from lichens (Fig. 5.1a). It has a mauve (purple) colour in distilled water. When added to an ac
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NATURAL INDICATOR – TURMERIC Activity 5.2: * Take a tablespoonful of turmeric powder. Add a little water and make a paste. * Make turmeric paper by depositing tu
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NATURAL INDICATOR – CHINA ROSE Activity 5.3: * Collect some China rose (Gudhal ) petals and place them in a beaker. Add some warm water. * Keep the mi
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PHENOLPHTHALEIN We have learnt that acids turn blue litmus red and bases turn red litmus blue. Let us see what happens when an acid is mixed with a base. We are going to use an indicator you hav
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WHAT IS NEUTRALISATION? When an acidic solution is mixed with a basic solution, both the solutions neutralise the effect of each other. When an acid solution and a base solution are mixed in suitab
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INDIGESTION, ANT BITE Indigestion Our stomach contains hydrochloric acid. It helps us to digest food, as you have learnt in Chapter 2. But too much of acid in the stomach causes indigestion
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SOIL TREATMENT, FACTORY WASTES Soil treatment Excessive use of chemical fertilisers makes the soil acidic. Plants do not grow well when the soil is either too acidic or too basic. When the soil
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MICROORGANISMS AND ITS CLASSIFICATION You have seen several kinds of plants and animals. However, there are other living organisms around us which we normally cannot see. These are called
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WHERE DO ORGANISMS LIVE? Microorganisms may be single-celled like bacteria, some algae and protozoa, or multicellular, such as many algae and fungi. They live in all types of environment, ranging f
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MICROORGANISMS AND US Microorganisms play an important role in our lives. Some of them are beneficial in many ways whereas some others are harmful and cause diseases. Let us study about them in det
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MAKING OF CURD AND BREAD You have learnt in Class VII that milk is turned into curd by bacteria. Curd contains several micro- organisms. Of these, the bacterium, Lactobacillus promotes t
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COMMERCIAL AND MEDICAL USE OF MICROORGANISMS Commercial use of microorganisms Microorganisms are used for the large scale production of alcohol, wine and acetic acid (vinegar). Yeast is used for
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VACCINE When a disease-carrying microbe enters our body, the body produces antibodies to fight the invader. The body also remembers how to fight the microbe if it enters again. If dead or weakened
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INCREASING SOIL FERTILITY AND CLEANING THE ENVIRONMENT Increasing soil fertility Some bacteria (Fig. 2.7) are able to fix nitrogen from the atmosphere to enrich soil with nitrogen and increase
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DISEASE CAUSING MICROORGANISMS IN HUMANS Microorganisms are harmful in many ways. Some of the microorganisms cause diseases in human beings, plants and animals. Such disease-causing microorgan
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DISEASE CAUSING MICROORGANISMS IN ANIMALS AND PLANTS Disease causing microorganisms in animals Several microorganisms not only cause diseases in humans and plants, but also in other animals
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FOOD POISONING Boojho was invited by his friend to a party and he ate a variety of foodstuff. On reaching home he started vomiting and had to be taken to a hospital. The doctor said that this condi
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CHEMICAL METHOD In Chapter 1, we have learnt about the methods used to preserve and store food grains. How do we preserve cooked food at home? You know that bread left unused under moist conditions
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PRESERVATION BY COMMON SALT & SUGAR Common salt has been used to preserve meat and fish for ages. Meat and fish are covered with dry salt to check the growth of bacteria. Salting is also used t
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PRESERVATION BY OIL AND VINEGAR Use of oil and vinegar prevents spoilage of pickles because bacteria cannot live in such an environment. Vegetables, fruits, fish and meat are often preserved by thi
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HEAT AND COLD TREATMENTS, STORAGE AND PACKING Heat and cold treatments You must have observed your mother boiling milk before it is stored or used. Boiling kills many microorganisms. &
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NITROGEN FIXATION AND NITROGEN CYCLE You have learnt about the bacterium Rhizobium in Classes VI and VII. It is involved in the fixation of nitrogen in leguminous plants (pulses). Recall that Rhizo
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WHAT IS POLLUTION? Paheli and Boojho were very excited to know that Taj Mahal in Agra is one of the seven wonders of the world. But they were disappointed to hear that the beauty of this monum
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WHAT IS AIR POLLUTION? We can survive for some time without food, but we cannot survive even for a few minutes without air. This simple fact tells us how important clean air is to us. &nbs
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HOW DOES AIR GET POLLUTED? The substances which contaminate the air are called air pollutants. Sometimes, such substances may come from natural sources like smoke and dust arising from forest fires
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CASE STUDY – THE TAJ MAHAL Over the past 2 decades, India’s most famous tourist attraction, Taj Mahal located in Agra (Fig. 18.4), has become a matter of concern. Experts have warned th
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GREENHOUSE EFFECT You know that the sun’s rays warm the earth’s surface. A part of the radiation that falls on the earth is absorbed by it and a part is reflected back into space.
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WHAT CAN BE DONE? What can we do to reduce air pollution? There are many success stories in our fight against air pollution. For example, a few years ago, Delhi was one of the most polluted citi
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WHAT ARE WATER POLLUTANTS? In Class VII you learnt that water is a precious resource. Think and list the various activities in which we need water. We saw that water is becoming scarce due to the i
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HOW DOES WATER GET POLLUTED? – CASE STUDY Ganga is one of the most famous rivers of India (Fig. 18.7). It sustains most of the northern, central and eastern Indian population. Millions of peo
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WHAT IS POTABLE WATER AND HOW IS WATER PURIFIED? Activity 18.7: * Let us construct a water filter with simple, everyday materials. * Take a plastic bottle an
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WHAT CAN BE DONE? Activity 18.8: * Investigate the level of awareness about water pollution in your area. * Collect data on the sources of drinking water a
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INTRODUCTION How do you come to know that a 'period’ is over in your school? You come to know easily that someone is at your door when he knocks or you hear the sound of the door
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SOUND IS PRODUCED BY A VIBRATING BODY Touch the school bell when not in use. What do you feel? Again touch it when producing sound. Can you feel it vibrating? Activity 13.1: (A vibrating body pr
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SOUND PRODUCED BY HUMANS Speak loudly for a while or sing a song or buzz like a bee. Put your hand on your throat as shown in Fig. 13.8. Do you feel any vibrations? In humans, the sound is
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SOUND NEEDS A MEDIUM FOR PROPAGATION When you call up your friend who is standing at a distance, your friend is able to hear your voice. How does the sound propagate or travel to her? Activity 1
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WE HEAR SOUND THROUGH EARS The shape of the outer part of the ear is like a funnel. When sound enters it, it travels down a canal at the end of which there is a thin stretched membrane. It is calle
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AMPLITUDE, TIME PERIOD AND FREQUENCY OF A VIBRATION We have learnt that the to and fro motion of an object is known as vibration. This motion is also called oscillatory motion . You have already
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LOUDNESS AND PITCH Activity 13.11: * Take a metallic tumbler and a tablespoon. * Strike the tablespoon gently at the brim of the tumbler. * Hear the sound
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AUDIBLE AND INAUDIBLE SOUNDS We know that we need a vibrating body for the production of sound. Can we hear the sound of all vibrating bodies? The fact is that sounds of frequencies less than about
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NOISE AND MUSIC We hear different types of sounds around us. Is the sound always pleasing? Does a sound sometimes cause discomfort to you? Some sounds are pleasant to the ear, whereas some are not.
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NOISE POLLUTION You already know about air pollution. Presence of unwanted gases and particles in the air is called air pollution. Similarly, the presence of excessive or unwanted sounds in the env
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INTRODUCTION Your elders might have cautioned you against touching an electrical appliance with wet hands. But do you know why it is dangerous to touch an electrical appliance with wet hands?
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HOW LIQUIDS CONDUCT ELECTRICITY? –ACTIVITY To test whether a liquid allows electric current to pass through it or not, we can use the same tester (Fig.14.1). Figure 14.1: a tester
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EXPLANATION OF CHEMICAL EFFECTS OF ELECTRIC CURRENT In Class VII, we have learnt some effects of electric current. Can you list these effects? What effect does the current produce when it flow
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ELECTROPLATING You know that a brand new bicycle has shiny handlebar and wheel rims. However, if these are accidentally scratched, the shiny coating comes off revealing a not so shiny surface benea
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The existence of atoms has been proposed since the time of early Indian and Greek philosophers (400 B.C.) who were of the view that atoms are the fundamental building blocks of matter. According to th
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DISCOVERY OF SUB-ATOMIC PARTICLES An insight into the structure of atoms was obtained from the experiments on electrical discharge through gases. Before we discuss these results we need to kee
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In 1897, British physicist J.J. Thomson measured the ratio of electrical charge (e-) to the mass of the electron (me ) by using cathode ray tube and applying electrical and magnetic field pe
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R.A. Millikan (1868-1953) devised a method known as the oil drop experiment (1906-14), to determine the charge on the electrons. He found the charge on the electron to&nb
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Discovery of Proton Electrical discharge carried out in the modified cathode ray tube led to the discovery of canal rays carrying positively charged particles. The characteristics of thes
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Observations obtained from the experiments mentioned in the previous sections have suggested that Dalton’s indivisible atom is composed of sub-atomic particles carrying positive and negative cha
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J.J. Thomson atomic model J. J. Thomson, in 1898, proposed that an atom possesses a spherical shape (radius approximately 10–10 m) in which the positive charge is uniformly
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rutherford's atomic model Rutherford and his students (Hans Geiger and Ernest Marsden) bombarded very thin gold foil with \(\alpha\)–particles. Rutherford’s famous \(\alph
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Drawbacks of Rutherford atomic model: As you have learned above, Rutherford nuclear model of an atom is like a small-scale solar system with the nucleus playing the role of the massi
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Atomic Number and Mass Number Atomic number (Z) The presence of a positive charge on the nucleus is due to the protons in the nucleus. As established earlier, the charge
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Representation of an Atom The composition of any atom can be represented by using the normal element symbol (X) with super-script on the left-hand side as the atomic mass number (A) and subscript (
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Historically, results observed from the studies of interactions of radiations with the matter have provided immense information regarding the structure of atoms and molecules. Neils Bohr utilized thes
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In the mid-nineteenth century, physicists actively studied the absorption and emission of radiation by heated objects. These are called thermal radiations. They tried to find out what the thermal radi
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Some of the experimental phenomena such as diffraction and interference can be explained by the wave nature of the electromagnetic radiation. However, the following are some of the obse
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Photoelectric Effect In 1887, H. Hertz performed a very interesting experiment in which electrons (or electric current) were ejected when certain metals (for example potassium, rubidium,
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How wonderful is the living world! The wide range of living types is amazing. The extraordinary habitats in which we find living organisms, be it cold mountains, deciduous forests, oceans, freshw
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1.2 DIVERSITY IN THE LIVING WORLD If you look around you will see a large variety of living organisms, be it potted plants, insects, birds, your pets, or other animals and plants. There are also se
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Classification Since it is nearly impossible to study all the living organisms, it is necessary to devise some means to make this possible. This process is classification. Classification is the pro
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Taxonomic Category Classification is not a single-step process but involves a hierarchy of steps in which each step represents a rank or category. Since the category is a
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Species Taxonomic studies consider a group of individual organisms with fundamental similarities as a species. One should be able to distinguish one species from the other closely relate
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Order You have seen earlier that categories like species, genus, and families are based on a number of similar characters. Generally, order and other higher taxonomic categories are identified base
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Taxonomical aids Taxonomic studies of various species of plants, animals, and other organisms are useful in agriculture, forestry, industry, and in general in knowing our bio-resources and their di
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Museum Biological museums are generally set up in educational institutes such as schools and colleges. Museums have collections of preserved plant and animal specimens for study a
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The Periodic Table is arguably the most important concept in chemistry, both in principle and in practice. It is the everyday support for students, it suggests new avenues of research to professionals
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Aristotle Classification Since the dawn of civilization, there have been many attempts to classify living organisms. It was done instinctively not using criteria that were scientific but
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Five Kingdom Classification R.H. Whittaker (1969) proposed a Five Kingdom Classification. The kingdoms defined by him were named Monera, Protista, Fungi, Plantae, and Animalia. The main c
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WHAT IS PHYSICS ? Humans have always been curious about the world around them.The night sky with its bright celestial objects has fascinated humans since time immemorial. The regular re
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Humans have always been curious about the world around them.The night sky with its bright celestial objects has fascinated humans since time immemorial. The regular repetitions of the day and night,
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SCOPE AND EXCITEMENT OF PHYSICS We can get some idea of the scope of physics by looking at its various sub-disciplines. Basically,there are two domains of interest : macroscopic and
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PHYSICS,TECHNOLOGY AND SOCIETY The connection between physics, technology and society can be seen in many examples.The discipline of thermodynamics arose from the need to understand and improve the
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FUNDAMENTAL FORCES IN NATURE We all have an intuitive notion of force. In our experience, force is needed to push, carry or throw objects, deform or break them. We also experience the impact of for
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Gravitational Force The gravitational force is the force of mutual attraction between any two objects by virtue of their masses.It is a universal force. Every object experiences this force due to e
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Electromagnetic Force Electromagnetic force is the force between charged particles. In the simpler case when charges are at rest, the force is given by Coulomb’s law : attractive for unlike c
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Strong Nuclear Force The strong nuclear force binds protons and neutrons in a nucleus. It is evident that without some attractive force,a nucleus will be unstable due to the electric repulsion betw
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Towards Unification of Forces We remarked in section 1.1 that unification is a basic quest in physics.Great advances in physics often amount to unification of different theories and domains.Ne
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NATURE OF PHYSICAL LAWS Physicists explore the universe.Their investigations, based on scientific processes, range from particles that are smaller than atoms in size to stars that are very far away
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Introduction of Units and Measurements Measurement of any physical quantity involves comparison with a certain basic,arbitrarily chosen, internationally accepted reference standard called unit.The
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THE INTERNATIONAL SYSTEM OF UNITS In earlier time scientists of different countries were using different systems of units for measurement.Three such systems, the CGS, the FPS (or British) system an
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MEASUREMENT OF LENGTH You are already familiar with some direct methods for the measurement of length.For example, a metre scale is used for lengths from 10–3 m to 102m A verni
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Estimation of Very Small Distances: Size of a Molecule To measure a very small size,like that of a molecule (10–8 m to 10–10 m), we have to adopt special methods. We cannot use a screw
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Range of Lengths The sizes of the objects we come across in the universe vary over a very wide range.These may vary from the size of the order of 10–14 m of the tiny nucleus of an atom to the
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MEASUREMENT OF MASS Mass is a basic property of matter. It does not depend on the temperature, pressure or location of the object in space.The SI unit of mass is kilogram (kg). It is defined by tak
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Ranges of Masses The masses of the objects,we come across in the universe, vary over a very wide range.These may vary from tiny mass of the order of 10-30 kg of an electron to the huge mass of abou
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Measurement of Time To measure any time interval we need a clock.We now use an atomic standard of time, which is based on the periodic vibrations produced in a cesium atom. This is the basis of the
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ACCURACY, PRECISION OF INSTRUMENTS AND ERRORS IN MEASUREMENT Measurement is the foundation of all experimental science and technology.The result of every measurement by any measuring inst
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Systematic Errors The systematic errors are those errors that tend to be in one direction, either positive or negative.Some of the sources of systematic errors are : (a).Inst
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Random Errors The random errors are those errors, which occur irregularly and hence are random with respect to sign and size.These can arise due to random and unpredictable fluctuations in exp
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Least Count Error The smallest value that can be measured by the measuring instrument is called its least count.All the readings or measured values are good only up to this value. The
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Absolute Error, Relative Error and Percentage Error (a)Suppose the values obtained in several measurements are a1,a2, a3 ...., a .The arithmetic mean of these values is taken as the best possi
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Combination of Errors If we do an experiment involving several measurements, we must know how the errors in all the measurements combine. For example,mass density is obtained by deviding mass by th
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SIGNIFICANT FIGURES As discussed above, every measurement involves errors. Thus, the result of measurement should be reported in a way that indicates the precision of measurement. Normally, the rep
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Rules for Arithmetic Operations with Significant Figures The result of a calculation involving approximate measured values of quantities (i.e. values with limited number of significant figures) mus
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Rounding off the Uncertain Digits The result of computation with approximate numbers, which contain more than one uncertain digit, should be rounded off. The rules for rounding off numbers to the
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Rules for Determining the Uncertainty in the Results of Arithmatic Calculations The rules for determining the uncertainty or error in the number/measured quantity in arithmetic operations can be un
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DIMENSIONS OF PHYSICAL QUANTITIES The nature of a physical quantity is described by its dimensions. All the physical quantities represented by derived units can be expressed in terms of s
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DIMENSIONAL FORMULAE AND EQUATIONS The expression which shows how and which of the base quantities represent the dimensions of a physical quantity is called the dimensional form
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What is Dimensional Analysis? The recognition of concepts of dimensions, which guide the description of physical behaviour is of basic importance as only those physical quantities can be added
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Checking the Dimensional Consistency of Equations The magnitudes of physical quantities may be added together or subtracted from one another only if they have the same dimensions. In other wor
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Deducing Relation among the Physical Quantities The method of dimensions can sometimes be used to deduce relation among the physical quantities. For this we should know the dependence of the physic
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INTRODUCTION Motion is common to everything in the universe. We walk, run and ride a bicycle. Even when we are sleeping, air moves into and out of our lungs, and blood flows in arteries and ve
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Position Earlier you learnt that motion is a change in the position of an object with time. In order to specify the position, we need to use a reference point and a set of axes. It is convenient to
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Path Length Consider the motion of a car along a straight line. We choose the x-axis such that it coincides with the path of the car’s motion and origin of the axis as the point from whe
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Displacement It is useful to define another quantity displacement as the change in position. Let x1 and x2 be the positions of an object t at time and t .Then its displacement,denote
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Average Velocity and Average Speed When an object is in motion, its position changes with time. But how fast is the position changing with time and in what direction? To describe this, we define th
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INSTANTANEOUS VELOCITY AND INSTANTANEOUS SPEED The average velocity tells us how fast an object has been moving over a given time interval but does not tell us how fast it moves at different instan
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ACCELERATION The velocity of an object, in general, changes during its course of motion. How to describe this change? Should it be described as the rate of change in velocity with distance or
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ACCELERATION The velocity of an object, in general, changes during its course of motion. How to describe this change? Should it be described as the rate of change in velocity with distance or
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KINEMATIC EQUATIONS FOR UNIFORMLY ACCELERATED MOTION For uniformly accelerated motion, we can derive some simple equations that relate displacement (x), time taken (t), initial velocity ( 
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RELATIVE VELOCITY You must be familiar with the experience of travelling in a train and being overtaken by another train moving in the same direction as you are. While that train must be travelling
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INTRODUCTION TO MOTION IN A PLANE In the last chapter we developed the concepts of position, displacement, velocity and acceleration that are needed to describe the motion of an object along a stra
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WHAT ARE SCALARS AND VECTORS In physics, we can classify quantities as scalars or vectors.Basically, the difference is that a direction is associated with a vector but not with a scalar. A scalar q
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POSITION AND DISPLACEMENT VECTORS To describe the position of an object moving in a plane, we need to choose a convenient point, say O as origin. Let P and \(% MathType!MTEF!2!1!+- % feaagKart1ev2
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EQUALITY OF VECTORS Two vectors A and B are said to be equal if, and only if, they have the same magnitude and the same direction.** Figure 4.2(a) shows two equal vectors A and B.
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MULTIPLICATION OF VECTORS BY REAL NUMBERS Multiplying a vector A with a positive number \(\lambda\) gives a vector whose magnitude is changed by the factor \(\lambda\) but the direction is the
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ADDITION AND SUBTRACTION OF VECTORS-GRAPHICAL METHOD As mentioned in section 4.2, vectors, by definition, obey the triangle law or equivalently, the parallelogram law of addition. We shall now desc
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RESOLUTION OF VECTORS Let a and b be any two non-zero vectors in a plane with different directions and let A be another vector in the same plane(Fig. 4.8). A can be expressed as a sum of two vector
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VECTOR ADDITION Although the graphical method of adding vectors helps us in visualising the vectors and the resultant vector, it is sometimes tedious and has limited accuracy. It is
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Position Vector and Displacement In this section we shall see how to describe motion in two dimensions using vectors. The position vector r of a particle P located in a plane wit
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Velocity The average velocity \(% MathType!MTEF!2!1!+- % feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqq
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Velocity The average velocity \(% MathType!MTEF!2!1!+- % feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqq
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Acceleration The average acceleration a of an object for a time interval \(\Delta\)t moving in x-y plane is the change in velocity divided by the time interval : \(% MathType!MTEF!2!1!+- % feaa
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Motion in a Plane with Constant Acceleration Suppose that an object is moving in x-y plane and its acceleration a is constant. Over an interval of time, the average acceleration will equal this con
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Relative Velocity in Two Dimensions The concept of relative velocity, introduced in section 3.7 for motion along a straight line, can be easily extended to include motion in a plane or in three
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Explanation of Projectile Motion As an application of the ideas developed in the previous sections, we consider the motion of a projectile. An object that is in flight after being thr
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Equation of path of a projectile What is the shape of the path followed by the projectile? This can be seen by eliminating the time between the expressions for x and y as given in Eq. (4.38). We ob
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Time of maximum height How much time does the projectile take to reach the maximum height ? Let this time be denoted by tm. Since at this point, vy= 0, we have from Eq. (4.39): \(% MathType!MTEF
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Time of maximum height The maximum height hm reached by the projectile can be calculated by substituting t = tm in Eq. (4.38) : \(% MathType!MTEF!2!1!+- % feaagKart1ev2aaatCvAUfe
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Horizontal range of a projectile The horizontal distance travelled by a projectile from its initial position (x = y = 0) to the position where it passes y = 0 during its fall is called the horizont
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Explanation of Uniform Circular Motion When an object follows a circular path at a constant speed, the motion of the object is called uniform circular motion.The word “uniform” refers
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INTRODUCTION In the preceding Chapter, our concern was to describe the motion of a particle in space quantitatively. We saw that uniform motion needs the concept of velocity alone whereas non-unifo
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Aristotle's Fallacy The question posed above appears to be simple.However, it took ages to answer it.Indeed, the correct answer to this question given by Galileo in the seventeenth century was
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The Law of Inertia Galileo studied motion of objects on an inclined plane. Objects (i) moving down an inclined plane accelerate, while those (ii) moving up retard. (iii) Motion on a horizontal plan
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Explanation of Newton's First Law Galileo’s simple,but revolutionary ideas dethroned Aristotelian mechanics.A new mechanics had to be developed.Thistask was accomplished almost singl
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Newton's Second Law-Momentum The law refers to the simple case when the net external force on a body is zero.The second law of motion refers to the general situation when there i
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Newton's Second Law-Impulse We sometimes encounter examples where a large force acts for a very short duration producing a finite change in momentum of the body. For example, when a ball hits a
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Explanation of Newton's Third Law of Motion The second law relates the external force on a body to its acceleration. What is the origin of the external force on the body ? What agency provides
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Conservation of Momentum The second and third laws of motion lead to an important consequence: the law of conservation of momentum.Take a familiar example. A bullet is fired from a gun. If the forc
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Equilibrium of a Particle Equilibrium of a particle in mechanics refers to the situation when the net external force on the particle is zero*.According to the first law, thismeans that, the pa
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Explanation of Common forces In Mechanics In mechanics, we encounter several kinds of forces.The gravitational force is, of course, pervasive. Every object on the earth experiences the force of gra
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Friction Let us return to the example of a body of mass m at rest on a horizontal table. The force of gravity (mg) is cancelled by the normal reaction force (N) of the table. Now suppose
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Friction A body like a ring or a sphere rolling without slipping over a horizontal plane will suffer no friction, in principle. At every instant, there is just one point of contact betwee
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Explanation of Circular Motion We have seen in Chapter 4 that acceleration of a body moving in a circle of radius R with uniform speed \(v\) is \(v\) 2/R directed towards the centre.According to th
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How can problem be solved in Mechanics The three laws of motion that you have learnt in this chapter are the foundation of mechanics. You should now be able to handle a large variety of p
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INTRODUCTION The terms ‘work’, ‘energy’ and ‘power’ are frequently used in everyday language. A farmer ploughing the field, a construction worker carrying bricks
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Notions of Work and Kinetic Energy : The Work Energy Theorem The following relation for rectilinear motion under constant acceleration a has been encountered in Chapter 3, \(v\)2 - u2
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Explanation of Work As seen earlier, work is related to force and the displacement over which it acts.Consider a constant force F acting on an object of mass m. The object undergoes a displacement
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Explanation of Kinetic Energy As noted earlier, if an object of mass m has velocity v, its kinetic energy K is \(% MathType!MTEF!2!1!+- % feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn %
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Explanation of Work Done by A Variable Force A constant force is rare. It is the variable force, which is more commonly encountered. Fig. 6.3 is a plot of a varying force in one dimension. If th
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The Work-Energy Theorem for Variable Force We are now familiar with the concepts of work and kinetic energy to prove the work-energy theorem for a variable force. We confine ourselves to
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Explanation of Potential Energy The word potential suggests possibility or capacity for action. The term potential energy brings to one’s mind ‘stored’ energy. A stretched bow-str
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The Conservation of Mechanical Energy For simplicity we demonstrate this important principle for one-dimensional motion. Suppose that a body undergoes displacement \(\Delta\)x under the action of a
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Various Forms of Energy: Heat, Chemical Energy and Electrical Energy In the previous section we have discussed mechanical energy. We have seen that it can be classified into two distinct categories
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Various Forms of Energy: Heat, Chemical Energy and Electrical Energy We have seen that the frictional force is not a conservative force. However, work is associated with the force of friction, Exam
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Various Forms of Energy: Heat, Chemical Energy and Electrical Energy One of the greatest technical achievements of humankind occurred when we discovered how to ignite and control fire. We learnt to
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Various Forms of Energy: Heat, Chemical Energy and Electrical Energy The flow of electrical current causes bulbs to glow, fans to rotate and bells to ring.There are laws governing the attraction an
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The Equivalence of Mass and Energy Till the end of the nineteenth century, physicists believed that in every physical and chemical process, the mass of an isolated system is conserved. Matter
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The Potential Energy of a Spring The spring force is an example of a variable force which is conservative. Fig. 6.7 shows a block attached to a spring and resting on a smooth horizontal surface.The
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Nuclear Energy The most destructive weapons made by man, the fission and fusion bombs are manifestations of Table 6.3.&n
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The Principle of Conservation of Energy We have seen that the total mechanical energy of the system is conserved if the forces doing work on it are conservative.If some of the forces involved are n
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Power Often it is interesting to know not only the work done on an object, but also the rate at which this work is done. We say a person is physically fit if he not only climbs four floors of a bui
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Introduction In physics we study motion (change in position).At the same time, we try to discover physical quantities, which do not change in a physical process. The laws of momentum and energy con
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Elastic and Inelastic Collisions In all collisions the total linear momentum is conserved; the initial momentum of the system is equal to the final momentum of the system.One can arg
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Collisions in One Dimension Consider first a completely inelastic collision in one dimension. Then, in Fig. 6.10, \(% MathType!MTEF!2!1!+- % feaagKart1ev2aaatCvAUfeBSju
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Collisions in Two Dimension Fig. 6.10 also depicts the collision of a moving mass m1 with the stationary mass m2.Linear momentum is conserved in such a collision. Since momen
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Need of Classifying Elements We know by now that the elements are the basic units of all types of matter. In 1800, only 31 elements were known.By 1865, the number of identified elements had mo
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Dobereiner's, Newlands',and Mendeleev’s Predictions Classification of elements into groups and development of Periodic Law and Periodic Table are the consequences of systematisi
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Explanation of Modern Periodic Law We must bear in mind that when Mendeleev developed his Periodic Table, chemists knew nothing about the internal structure of atom. However, the beginnin
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NOMENCLATURE OF ELEMENTS WITH ATOMIC NUMBERS > 100 The naming of the new elements had been traditionally the privilege of the discoverer (or discoverers) and the suggested name was ratified
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Electronic Configurations in Periods In the preceding unit we have learnt that an electron in an atom is characterised by a set of four quantum numbers, and the principal quantum number (n ) define
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Group wise Electonic Configurations Elements in the same vertical column or group have similar valence shell electronic configurations, the same number of electrons in the outer orbitals, an
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Introduction to s-p-d-f-block Elements The aufbau (build up) principle and the electronic configuration of atoms provide a the Periodic Table. More about these elements will be discussed later
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The s-Block Elements The elements of Group 1 (alkali metals) and Group 2 (alkaline earth metals) which have ns1 and ns2 outermost electronic configuration belong to the s-Block Elements.
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The p-Block Elements The p-Block Elements comprise those belonging to Group 13 to 18 and these together with the s-block elements are called the Representative Elements or Main Group Elements.
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The d-Block Elements (Transition Elements) These are the elements of Group 3 to 12 in the centre of the Periodic Table.These are characterised by the filling of inner d orbitals by electrons and ar
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The f-Block Elements(Inner-Transition Elements) The two rows of elements at the bottom of the Periodic Table, called the Lanthanoids, Ce(Z = 58) – Lu(Z = 71) and Actinoids, Th(Z = 9
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Metals, Non-metals and Metalloids In addition to displaying the classification of elements into s-, p-, d-, and f-blocks, Fig. 3.3 shows another broad classification of elements based on their prop
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Introduction to Trends in Physical Properties There are many observable patterns in the physical and chemical properties of elements as we descend in a group or move across a period in the Periodic
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(a) Atomic Radius You can very well imagine that finding the size of an atom is a lot more complicated than measuring the radius of a ball. Do you know why? Firstly, because the size of a
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(b) Ionic Radius The removal of an electron from an atom results in the formation of a cation, whereas gain of an electron leads to an anion. The ionic radii can be estimated by measuring the dista
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ionization enthalpy A quantitative measure of the tendency of an element to lose electron is given by its Ionization Enthalpy.It represents the energy required to remove an electron from an isolate
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(d) Electron Gain Enthalpy When an electron is added to a neutral gaseous atom (X) to convert it into a negative ion, the enthalpy change accompanying the process is defined as the Electron Gain En
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Electronegativity A qualitative measure of the ability of an atom in a chemical compound to attract shared electrons to itself is called electronegativity. Unlike ionization enthalpy and electron
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Periodicity Of Valence or Oxidation States Most of the trends in chemical properties of elements, such as diagonal relationships, inert pair effect, effects of lanthanoid contraction etc. will be d
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Anomalous Properties of Second Period Elements The first element of each of the groups 1 (lithium) and 2 (beryllium) and groups 13-17 (boron to fluorine) differs in many respects from the other mem
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Periodic Trends and Chemical Reactivity We have observed the periodic trends in certain fundamental properties such as atomic and ionic radii, ionization enthalpy, electron gain enthalpy and valenc
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Introduction Matter is made up of one or different type of elements. Under normal conditions no other element exists as an independent atom in nature, except noble gases. However, a g
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Kossel-Lewis Approach to Chemical Bonding In order to explain the formation of chemical bond in terms of electrons, a number of attempts were made, but it was only in 1916 when Kössel and Lewi
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Octet Rule and Covalent Bond Octet Kössel and Lewis in 1916 developed an important theory of chemical combination between atoms known as electronic theory of chemical bonding. Acc
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Lewis Representation of Simple Molecules (The Lewis Stuctures) The Lewis dot structures provide a picture of bonding in molecules and ions in terms of the shared pairs of electrons and th
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Formal Charge Lewis dot structures, in general, do not represent the actual shapes of the molecules. In case of polyatomic ions, the net charge is possessed by the ion as a whole and not by a parti
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Limitations of the Octet Rule The octet rule, though useful, is not universal. It is quite useful for understanding the structures of most of the organic compounds and it applies mainly to the seco
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Explanation of Ionic or Electrovalent Bond From the Kössel and Lewis treatment of the formation of an ionic bond, it follows that the formation of ionic compounds would primarily depend upon:
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Lattice Enthalpy The Lattice Enthalpy of an ionic solid is defined as the energy required to completely separate one mole of a solid ionic compound into gaseous constituent ions. For example, the l
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Bond Length,Bond Angle Bond length is defined as the equilibrium distance between the nuclei of two bonded atoms in a molecule. Bond lengths are measured by spectroscopic, X-ray diffraction and ele
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Bond Length, Both Angle It is defined as the angle between the orbitals containing bonding electron pairs around the central atom in a molecule/complex ion. Bond angle is expressed in degree which
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Bond Enthalpy It is defined as the amount of energy required to break one mole of bonds of a particular type between two atoms in a gaseous state.The unit of bond enthalpy is kJ mol–1. For ex
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Bond Order In the Lewis description of covalent bond, the Bond Order is given by the number of bonds between the two atoms in a molecule.The bond order, for example in H2 (with a single shared
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Resonance Structures It is often observed that a single Lewis structure is inadequate for the representation of a molecule in conformity with its experimentally determined parameters. For example,
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Polarity of Bonds The existence of a hundred percent ionic or covalent bond represents an ideal situation. In reality no bond or a compound is either completely covalent or ionic. Even in
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Expalnation of Valence Bond Theory As already explained, Lewis concept is unable to explain the shapes of molecules. This theory provides a simple procedure to predict the shapes of covalent molecu
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Orbital Overlap Concept In the formation of hydrogen molecule, there is a minimum energy state when two hydrogen atoms are so near that their atomic orbitals undergo partial interpenetration. This
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Directional Properties of Bonds As we have already seen, the covalent bond is formed by overlapping of atomic orbitals.The molecule of hydrogen is formed due to the overlap of 1s-orbitals of two H
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Overlapping of Atomic Orbitals When orbitals of two atoms come close to form bond, their overlap may be positive, negative or zero depending upon the sign (phase) and direction of orientation of am
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Types of Overlapping and Nature of Covalent Bonds and Strength of Bonds The covalent bond may be classified into two types depending upon the types of overlapping: (i)
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Explanation of Hybridisation In order to explain the characteristic geometrical shapes of polyatomic molecules like CH4, NH3 and H2O etc., Pauling introduced the concept of hybridisation. Acco
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Types of Hybridisation - sp hybridisation There are various types of hybridisation involving s, p and d orbitals.The different types of hybridisation are as under: 1. sp hybridisation:
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Types of Hybridisation - sp2 hybridisation sp2 hybridisation : In this hybridisation there is involvement of one s and two p-orbitals in order to form three equivalent sp2 hybridised orbitals. For
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Types of Hybridisation - sp3 hybridisation sp3 hybridisation: This type of hybridisation can be explained by taking the example of CH4 molecule in which there is mixing of one s-orbital and th
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Other Examples of sp3,sp2 and sp Hybridisation sp3 Hybridisation in C2H6 molecule: In ethane molecule both the carbon atoms assume sp3 hybrid state. One of the four sp3 hy
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Hybridisation Of Elements involving d Oebitals The elements present in the third period contain d orbitals in addition to s and p orbitals.The energy of the 3d orbitals are comparable to the energy
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Explanation of Molecular Orbital Theory Molecular orbital (MO) theory was developed by F. Hund and R.S. Mulliken in 1932.The salient features of this theory are : 1. The electrons in a
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Linear Combination of Atomic Orbitals (LCAO) and Conditions for the Combination According to wave mechanics, the atomic orbitals can be expressed by wave functions (\(% MathType!MTE
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Types of Molecular Orbitals Molecular orbitals of diatomic molecules are designated as \(\sigma\) (sigma), \(\pi\) (pi), \(% MathType!MTEF!2!1!+- % feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLb
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Energy Level Diagram for Molecular Orbitals We have seen that 1s atomic orbitals on two atoms form two molecular orbitals designated as \(\sigma\)1s and \(\sigma\)*1s. In the same manner,
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Electronic Configuration and Molecular Behaviour The distribution of electrons among various molecular orbitals is called the electronic configuration of the molecule.From the electronic configurat
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Bonding in Some Homonuclear Diatomic Molecules Bond Order Bond order (b.o.) is defined as one half the difference between the number of electrons present in the bonding and the antibonding orbit
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Explanation, Cause of Formation and type of H-bonding HYDROGEN BONDING Nitrogen, oxygen and fluorine are the higly electronegative elements. When they are attached to a hydrogen atom to form cov
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Introduction In previous units we have learnt about the properties related to single particle of matter, such as atomic size, ionization enthalpy, electronic charge density, molecular shape and pol
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Introduction In previous units we have learnt about the properties related to single particle of matter, such as atomic size, ionization enthalpy, electronic charge density, molecular shape and pol
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INTRODUCTION Chemical energy stored by molecules can be released as heat during chemical reactions when a fuel like methane, cooking gas or coal burns in air. The chemical energy may also be used t
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Chemical equilibria are important in numerous biological and environmental processes. For example, equilibria involving O2 molecules and the protein hemoglobin play a crucial role in the transpor
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INTRODUCTION Early in our lives, we become aware of the tendency of all material objects to be attracted towards the earth. Anything thrown up falls down towards the earth, going uphill is lot 
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When you look around, you will observe different animals with different structures and forms. As over a million species of animals have been described till now, the need for classification becomes all
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The wide range in the structure of higher plants will never fail to fascinate us. Even though the angiosperms show such a large diversity in external structure or morphology, they are all characterise
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In the previous chapter, we looked at the broad classification of living organisms under the system proposed by Whittaker (1969) wherein he suggested the Five Kingdom classification viz. Mon
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When you look around, you see both living and non-living things. You must have wondered and asked yourself – ‘what is it that makes an organism living, or what is it that an inan
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Are you aware that all organisms, even the largest, start their life from a single cell? You may wonder how a single cell then goes on to form such large organisms. Growth and reproduction are charact
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There is a wide diversity in living organisms in our biosphere. Now a question that arises in our minds is: Are all living organisms made of the same chemicals, i.e., elements and compounds? You have
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All of us breathe to live, but why is breathing so essential to life? What happens when we breathe? Also, do all living organisms, including plants and microbes, breathe? If so, how? All
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All animals including human beings depend on plants for their food. Have you ever wondered from where plants get their food? Green plants, in fact, have to make or rather synthesise the food
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Have you ever wondered how water reaches the top of tall trees, or for that matter how and why substances move from one cell to the other, whether all substances move in a similar
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You have already studied the organisation of a flowering plant in Chapter 5. Have you ever thought about where and how the structures like roots, stems, leaves, flowers, fruits and seed
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As you have read earlier, oxygen (O2) is utilised by the organisms to indirectly break down simple molecules like glucose, amino acids, fatty acids, etc., to derive energy to perfor
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Food is one of the basic requirements of all living organisms. The major components of our food are carbohydrates, proteins and fats. Vitamins and minerals are also required in small quantities. Food
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You have learnt that all living cells have to be provided with nutrients, O2 and other essential substances. Also, the waste or harmful substances produced, have to be removed contin
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Animals accumulate ammonia, urea, uric acid, carbon dioxide, water and ions like Na+, K+, Cl–, phosphate, sulphate, etc., either by metabolic activities or by other means like excess ingestion.
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Movement is one of the significant features of living beings. Animals and plants exhibit a wide range of movements. Streaming of protoplasm in the unicellular organisms like Amoeba is a simple form of
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You have already learnt that the neural system provides a point-to-point rapid coordination among organs. The neural coordination is fast but short-lived. As the nerve fibres do not innervate all cell
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As you know, the functions of the organs/organ systems in our body must be coordinated to maintain homeostasis. Coordination is the process through which two or more organs interact and complement the
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Kingdom Monera-Archebacter,Eubacteria Archebacter These bacteria are special since they live in some of the most harsh habitats such as extreme salty areas (halophiles), hot springs (t
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Kingdom Protista - Chrysophytes,Dinoflagellates All single-celled eukaryotes are placed under Protista, but the boundaries of this kingdom are not well defined. What may be ‘a photo
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Kingdom Protista- Euglenoids, Slime Moulds and Protozoans Majority of them are fresh water organisms found in stagnant water. Instead of a cell wall, they have a protein rich layer called
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Kingdom Fungi - Phycomycetes , Ascomycetes The fungi constitute a unique kingdom of heterotrophic organisms. They show a great diversity in morphology and habitat. You must have seen fungi on a moi
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Kingdom Fungi - Basidiomycetes , Deuteromycetes Commonly known forms of basidiomycetes are mushrooms, bracket fungi or puffballs. They grow in soil, on logs and tree stumps and in living plant bodi
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Kingdom Plantae Kingdom Plantae includes all eukaryotic chlorophyll-containing organisms commonly called plants. A few members are partially heterotrophic such as the insectivorous plants or parasi
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Kingdom Animalia This kingdom is characterised by heterotrophic eukaryotic organisms that are multicellular and their cells lack cell walls. They directly or indirectly depend on plants for food. T
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Viruses , Viroids , Prions And Lichens In the five kingdom classification of Whittaker there is no mention of lichens and some acellular organisms like viruses, viroids and prions. These are brie
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In Chapter 7, we studied the rotation of the bodies and then realised that the motion of a body depends on how mass is distributed within the body. We restricted ourselves to simpler situati
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In Chapter 7, we studied the rotation of the bodies and then realised that the motion of a body depends on how mass is distributed within the body. We restricted ourselves to simpler situati
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Boyle discovered the law named after him in 1661. Boyle, Newton and several others tried to explain the behaviour of gases by considering that gases are made up of tiny atomic particles. The actual at
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We all have common sense notions of heat and temperature. Temperature is a measure of ‘hotness’ of a body. A kettle with boiling water is hotter than a box containing ice. In physics, we n
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INTRODUCTION Early in our lives, we become aware of the tendency of all material objects to be attracted towards the earth. Anything thrown up falls down towards the earth, going uphill i
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INTRODUCTION Early in our lives, we become aware of the tendency of all material objects to be attracted towards the earth. Anything thrown up falls down towards the earth, going uphill i
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Law of Orbits The three laws of Kepler can be stated as follows: 1.Law of orbits : All planets move in elliptical orbits with the Sun situated at one of the foci Fig. 8.1(
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2. Law of areas : The line that joins any planet to the sun sweeps equal areas in equal intervals of time (Fig. 8.2). This law comes from the observations that planets appear to move slower wh
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Explanation of Universal Law Of Gravitation Legend has it that observing an apple falling from a tree, Newton was inspired to arrive at an universal law of gravitation that led to an explanation of
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Central Forces We know the time rate of change of the angular momentum of a single particle about the origin is \(% MathType!MTEF!2!1!+- % feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv
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Explanation of The Gravitational Constant The value of the gravitational constant G entering the Universal law of gravitation can be determined experimentally and this was first done by English sci
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Earth's Acceleration Due to Gravity The earth can be imagined to be a sphere made of a large number of concentric spherical shells with the smallest one at the centre and the largest one at its
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Acceleration Due to Gravity Below and Above the surface of Earth Consider a point mass m at a height h above the surface of the earth as shown in Fig. 8.8(a).The radius of the earth is denoted by R
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Explanation of Gravitational Potential Energy We had discussed earlier the notion of potential energy as being the energy stored in the body at its given position. If the position of the particle c
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Explanation of Escape Speed If a stone is thrown by hand, we see it falls back to the earth. Of course using machines we can shoot an object with much greater speeds and with greater and great
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Explanation About Earth Satellites Earth satellites are objects which revolve around the earth. Their motion is very similar to the motion of planets around the Sun and hence Kepler&
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Energy of an Orbiting Satellites Using Eq. (8.35), the kinetic energy of the satellite in a circular orbit with speed \(v\) is \(% MathType!MTEF!2!1!+- % feaagKart1ev2aaatCvAUfeBSjuyZ
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Geostationary and Polar Satellites An interesting phenomenon arises if in we arrange the value of (RE + h) such that T in Eq. (8.37) becomes equal to 24 hours. If the circular orbit i
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Geostationary and Polar Satellites An interesting phenomenon arises if in we arrange the value of (RE + h) such that T in Eq. (8.37) becomes equal to 24 hours. If the circular orbit i
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India's Leap into Space India started its space programme in 1962 when Indian National Committee for Space Research was set up by the Government of India which was superseded by the Indian Spac
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What is Weightlessness Weight of an object is the force with which the earth attracts it. We are conscious of our own weight when we stand on a surface, since the surface exerts a force opposite to
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In this chapter, we shall study some common physical properties of liquids and gases. Liquids and gases can flow and are therefore, called fluids. It is this property that distinguishes liqu
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In previous chapter we have studied thermal properties of matter. In this chapter we shall study laws that govern thermal energy. We shall study the processes where work is converted into heat and vic
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In our daily life we come across various kinds of motions. You have already learnt about some of them, e.g., rectilinear motion and motion of a projectile. Both these motions are non-repetitive. We ha
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In the previous Chapter, we studied the motion of objects oscillating in isolation. What happens in a system, which is a collection of such objects? A material medium provides such an example. Here, e
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Chemistry deals with varieties of matter and change of one kind of matter into the other. Transformation of matter from one kind into another occurs through the various types of reactions.
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Hydrogen has the simplest atomic structure among all the elements around us in Nature. In atomic form it consists of only one proton and one electron. However, in elemental form it exists
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The s-block elements of the Periodic Table are those in which the last electron enters the outermost s-orbital. As the s-orbital can accommodate only two electrons, two groups (1 & 2)
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In p-block elements the last electron enters the outermost p orbital. As we know that the number of p orbitals is three and, therefore, the maximum number of electrons that can be accommodated in a se
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You have already studied about environment in your earlier classes. Environmental studies deal with the sum of all social, economical, biological, physical and chemical interrelations with
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The term ‘hydrocarbon’ is self-explanatory which means compounds of carbon and hydrogen only. Hydrocarbons play a key role in our daily life. You must be familiar with the terms ‘LPG
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In the previous unit you have learnt that the element carbon has the unique property called catenation due to which it forms covalent bonds with other carbon atoms. It also forms covalent bonds with a
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All of us have the experience of seeing a spark or hearing a crackle when we take off our synthetic clothes or sweater, particularly in dry weather. This is almost inevitable with ladies garments like
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In Chapters 6 and 8 (Class XI), the notion of potential energy was introduced. When an external force does work in taking a body from a point to another against a force like spring force or gravitatio
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INTRODUCTION In Chapter 1, all charges whether free or bound, were considered to be at rest. Charges in motion constitute an electric current. Such currents occur naturally in many situations. Ligh
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INTRODUCTION Both Electricity and Magnetism have been known for more than 2000 years. However, it was only about 200 years ago, in 1820, that it was realised that they were intimately related*. Dur
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Sources and fields Before we introduce the concept of a magnetic field B, we shall recapitulate what we have learnt in Chapter 1 about the electric field E. We have seen that the
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Magnetic Field, Lorentz Force Let us suppose that there is a point charge q (moving with a velocity v and, located at r at a given time t ) in presence of both the electric field
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Magnetic force on a current-carrying conductor We can extend the analysis for force due to magnetic field on a single moving charge to a straight rod carrying current. Consider a rod of a
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MOTION IN A MAGNETIC FIELD We will now consider, in greater detail, the motion of a charge moving in a magnetic field. We have learnt in Mechanics (see Class XI book, Chapter 6) that a force on a p
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VELOCITY SELECTOR You know that a charge q moving with velocity v in presence of both electric and magnetic fields experiences a force given by Eq. (4.3), that is, F = q (E
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CYCLOTRON The cyclotron is a machine to accelerate charged particles or ions to high energies. It was invented by E.O. Lawrence and M.S. Livingston in 1934 to investigate nuclear structure. The cyc
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VELOCITY SELECTOR You know that a charge q moving with velocity v in presence of both electric and magnetic fields experiences a force given by Eq. (4.3), that is, \(% MathType!MTEF!2!1!+- % fe
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VELOCITY SELECTOR You know that a charge q moving with velocity v in presence of both electric and magnetic fields experiences a force given by Eq. (4.3), that is, \(% MathType!MTEF!2!1!+- % fe
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CYCLOTRON The cyclotron is a machine to accelerate charged particles or ions to high energies. It was invented by E.O. Lawrence and M.S. Livingston in 1934 to investigate nuclear structure. The cyc
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Explanation of Biot-Savart Law All magnetic fields that we know are due to currents (or moving charges) and due to intrinsic magnetic moments of particles. Here, we shall study the relation be
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Explanation of Magnetic Field of a Circular Current Loop In this section, we shall evaluate the magnetic field due to a circular coil along its axis. The evaluation entails summing up the effect of
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Explanation of Ampere's Circuital Law There is an alternative and appealing way in which the Biot-Savart law may be expressed. Ampere’s circuital law considers an open surface with
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The solenoid and the toroid are two pieces of equipment which generate magnetic fields. The synchrotron uses a combination of both to generate the high magnetic fields required. In both, solenoid and
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The Toroid The toroid is a hollow circular ring on which a large number of turns of a wire are closely wound. It can be viewed as a solenoid which has been bent into a circular shape to close on it
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Force Between Two Parallel Current, The Ampere We have learnt that there exists a magnetic field due to a conductor carrying a current which obeys the Biot-Savart law. Further, we have learnt
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Roget's Spiral for Attraction Between Parallel Currents Magnetic effects are generally smaller than electric effects. As a consequence, the force between currents is rather small, because of th
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Torque on a Rectangular current loop in uniform magnetic field We now show that a rectangular loop carrying a steady current I and placed in a uniform magnetic field experiences a torque. It does n
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Circular current loop as a magnetic dipole In this section, we shall consider the elementary magnetic element: the current loop. We shall show that the magnetic field (at large distances) due to cu
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The magnetic dipole moment of a revolving electron In Chapter 12 we shall read about the Bohr model of the hydrogen atom. You may perhaps have heard of this model which was proposed by the Danish p
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Explanation of The Moving Coil Galvanometer Currents and voltages in circuits have been discussed extensively in Chapters 3. But how do we measure them? How do we claim that current in a circuit is
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Introduction Magnetic phenomena are universal in nature. Vast, distant galaxies, the tiny invisible atoms, humans and beasts all are permeated through and through with a host of magnetic fields fro
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One of the earliest childhood memories of the famous physicist Albert Einstein was that of a magnet gifted to him by a relative. Einstein was fascinated, and played endlessly with it. He wondered how
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Bar magnet as an equivalent solenoid In the previous chapter, we have explained how a current loop acts as a magnetic dipole (Section 4.10). We mentioned Ampere’s hypothesis that all magnetic
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The dipole in a uniform magnetic field The pattern of iron filings, i.e., the magnetic field lines gives us an approximate idea of the magnetic field B. We may at times be required to det
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The electrostatic analog Comparison of Eqs. (5.2), (5.3) and (5.6) with the corresponding equations for electric dipole (Chapter 1), suggests that magnetic field at large distances due to a bar mag
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Explanation of Magnetisum and Gauss's Law In Chapter 1, we studied Gauss’s law for electrostatics. In Fig 5.3(c), we see that for a closed surface represented by i , the number of lines l
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What is The Earth's Magnetism? Earlier we have referred to the magnetic field of the earth. The strength of the earth’s magnetic field varies from place to place on the earth’s
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Magnetic declination and dip Consider a point on the earth’s surface. At such a point, the direction of the longitude circle determines the geographic north-south direction, the line of longi
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Explanation of Magnetisation Intensity The earth abounds with a bewildering variety of elements and compounds. In addition, we have been synthesising new alloys, compounds and even elements. One wo
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The discussion in the previous section helps us to classify materials as diamagnetic, paramagnetic or ferromagnetic. In terms of the susceptibility \(% MathType!MTEF!2!1!+- % feaagKart1ev2aaatCvAU
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Paramagnetism Paramagnetic substances are those which get weakly magnetised when placed in an external magnetic field. They have tendency to move from a region of weak magnetic field to strong magn
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Ferromagnetism Ferromagnetic substances are those which gets strongly magnetised when placed in an external magnetic field. They have strong tendency to move from a region of weak magnetic field to
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Permanent Magnets and Electromagnets Substances which at room temperature retain their ferromagnetic property for a long period of time are called permanent magnets. Permanent magnets can be m
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Introduction Electricity and magnetism were considered separate and unrelated phenomena for a long time. In the early decades of the nineteenth century, experiments on electric current by Oersted,
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Explanation of The Faraday and Henry The discovery and understanding of electromagnetic induction are based on a long series of experiments carried out by Faraday and Henry. We shall now describe s
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Explanation of Magnetic Flux Faraday’s great insight lay in discovering a simple mathematical relation to explain the series of experiments he carried out on electromagnetic induction. Howeve
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Explanation of Faraday's Law of Induction From the experimental observations, Faraday arrived at a conclusion that an emf is induced in a coil when magnetic flux through the coil changes with t
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Lenz's Law and Conservation of Energy In 1834, German physicist Heinrich Friedrich Lenz (1804-1865) deduced a rule, known as Lenz’s law which gives the polarity of the induced emf in a cl
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Explanation of Motional Electromotive Force Let us consider a straight conductor moving in a uniform and time- independent magnetic field. Figure 6.10 shows a rectangular conductor PQRS in which th
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Energy Consideration : A Quantitative Study In Section 6.5, we discussed qualitatively that Lenz’s law is consistent with the law of conservation of energy. Now we shall explore this aspect f
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What are Eddy Currents? So far we have studied the electric currents induced in well defined paths in conductors like circular loops. Even when bulk pieces of conductors are subjected to changing m
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Electromagnetic Damping Take two hollow thin cylindrical pipes of equal internal diameters made of aluminium and PVC, respectively. Fix them vertically with clamps on retort stands. Take a sma
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Introduction to Inductance An electric current can be induced in a coil by flux change produced by another coil in its vicinity or flux change produced by the same coil. These two situations are de
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Mutual Inductance Consider Fig. 6.15 which shows two long co-axial solenoids each of length l. FIGURE 6.15 Two long coaxial solenoids of same length l.
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Self Inductance In the previous sub-section, we considered the flux in one solenoid due to the current in the other. It is also possible that emf is induced in a single isolated coil due to change
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Explanation of AC Generator The phenomenon of electromagnetic induction has been technologically exploited in many ways. An exceptionally important application is the generation of alternating curr
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INTRODUCTION We have so far considered direct current (dc) sources and circuits with dc sources. These currents do not change direction with time. But voltages and curre
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In Chapter 4, we learnt that an electric current produces magnetic field and that two current-carrying wires exert a magnetic force on each other. Further, in Chapter 6, we have seen that a magnetic f
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INTRODUCTION In 1637 Descartes gave the corpuscular model of light and derived Snell’s law. It explained the laws of reflection and refraction of light at an interface. The
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Nature has endowed the human eye (retina) with the sensitivity to detect electromagnetic waves within a small range of the electromagnetic spectrum. Electromagnetic radiation belonging to this region
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The Maxwell’s equations of electromagnetism and Hertz experiments on the generation and detection of electromagnetic waves in 1887 strongly established the wave nature of light. Towards the same
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By the nineteenth century, enough evidence had accumulated in favour of atomic hypothesis of matter. In 1897, the experiments on electric discharge through gases carried out by the English physicist J
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In the previous chapter, we have learnt that in every atom, the positive charge and mass are densely concentrated at the centre of the atom forming its nucleus. The overall dimensions of a nucleus are
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Devices in which a controlled flow of electrons can be obtained are the basic building blocks of all the electronic circuits. Before the discovery of transistor in 1948, such devices were mostly vacuu
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From our earlier studies, we know that liquids and gases are called fluids because of their ability to flow. The fluidity in both of these states is due to the fact that the molecules are free to move
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In normal life we rarely come across pure substances. Most of these are mixtures containing two or more pure substances. Their utility or importance in life depends on their composition. For example,
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Electrochemistry is the study of production of electricity from energy released during spontaneous chemical reactions and the use of electrical energy to bring about non-spontaneous chemical transform
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Chemistry, by its very nature, is concerned with change. Substances with well defined properties are converted by chemical reactions into other substances with different properties. For any chemical r
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Surface chemistry deals with phenomena that occur at the surfaces or interfaces. The interface or surface is represented by separating the bulk phases by a hyphen or a slash. For example, the interfac
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The history of civilisation is linked to the use of metals in antiquity in many ways. Different periods of early human civilisations have been named after metals. The skill of extraction of metals gav
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In Class XI, you have learnt that the p-block elements are placed in groups 13 to 18 of the periodic table. Their valence shell electronic configuration is ns2np1–6 (except He which has 1s2 conf
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Oxygen, sulphur, selenium, tellurium, polonium and livermorium constitute Group 16 of the periodic table. This is sometimes known as group of chalcogens. The name is derived from the Greek word for br
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Group 17 Elements Fluorine, chlorine, bromine, iodine, astatine and tennessine are members of Group 17. These are collectively known as the halogens (Greek halo means salt and gene
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Group 18 Elements Group 18 consists of elements: helium, neon, argon, krypton, xenon, radon and oganesson. All these are gases and chemically unreactive. They form very few compounds, becaus
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The d-block of the periodic table contains the elements of the groups 3-12 in which the d orbitals are progressively filled in each of the four long periods. The f-block consists of elements in which
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In the previous Unit we learnt that the transition metals form a large number of complex compounds in which the metal atoms are bound to a number of anions or neutral molecules by sharing of el
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The replacement of hydrogen atom(s) in an aliphatic or aromatic hydrocarbon by halogen atom(s) results in the formation of alkyl halide (haloalkane) and aryl halide (haloarene), respectively. Haloalka
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You have learnt that substitution of one or more hydrogen atom(s) from a hydrocarbon by another atom or a group of atoms result in the formation of an entirely new compound having altogether different
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In the previous Unit, you have studied organic compounds with functional groups containing carbon- oxygen single bond. In this Unit, we will study about the organic compounds containing carbon-oxygen
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Amines constitute an important class of organic compounds derived by replacing one or more hydrogen atoms of ammonia molecule by alkyl/aryl group(s). In nature, they occur among proteins, vitamins, al
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A living system grows, sustains and reproduces itself. The most amazing thing about a living system is that it is composed of non-living atoms and molecules. The pursuit of knowledge of what goes on
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Do you think that daily life would have been easier and colourful without the discovery and varied applications of polymers? The use of polymers in the manufacture of plastic buckets, cups and saucers
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By now, you have learnt the basic principles of chemistry and also realised that it influences every sphere of human life. The principles of chemistry have been used for the benefit of mankind. Think
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EQUILIBRIUM IN PHYSICAL PROCESSES The characteristics of system at equilibrium are better understood if we examine some physical processes. The most familiar examples are phase transforma
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Liquid-Vapour Equilibrium This equilibrium can be better understood if we consider the example of a transparent box carrying a U-tube with mercury (manometer). Drying agent like anhydrous calcium c
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Solid–Vapour Equilibrium Let us now consider the systems where solids sublime to vapour phase. If we place solid iodine in a closed vessel, after sometime the vessel gets filled u
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Solids in liquids We know from our experience that we can dissolve only a limited amount of salt or sugar in a given amount of water at room temperature. If we make a thick sugar syrup so
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Gases in liquids When a soda water bottle is opened, some of the carbon dioxide gas dissolved in it fizzes out rapidly. The phenomenon arises due to difference in solubility of carbon dioxide at di
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General Characteristics of Equilibria Involving Physical Processes For the physical processes discussed above, following characteristics are common to the system at equilibrium: 1
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EQUILIBRIUM IN CHEMICAL PROCESSES – DYNAMIC EQUILIBRIUM Analogous to the physical systems chemical reactions also attain a state of equilibrium. These reactions can occur both in forward and
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Dynamic Equilibrium – A Student’s Activity Equilibrium whether in a physical or in a chemical system, is always of dynamic nature. This can be demonstrated by the use of radio
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LAW OF CHEMICAL EQUILIBRIUM AND EQUILIBRIUM CONSTANT A mixture of reactants and products in the equilibrium state is called an equilibrium mixture. In this section we shall address a nu
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Six sets of experiments with varying initial conditions were performed, starting with only gaseous H2 and I2 in a sealed reaction vessel in first four experiments (1, 2, 3 and 4) and only HI
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PROBLEM 1 The following concentrations were obtained for the formation of NH3 from N2 and H2 at equilibrium at 500K. \(% MathType!MTEF!2!1!+- % feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvy
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HOMOGENEOUSEQUILIBRIA In a homogeneous system, all the reactants and products are in the same phase. For example,in the gaseous reaction, \(% MathType!MTEF!2!1!+- % feaa
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HETEROGENEOUS EQUILIBRIA Equilibrium in a system having more than one phase is called heterogeneous equilibrium.The equilibrium between water vapour and liquid water in a closed cont
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APPLICATIONS OF EQUILIBRIUM CONSTANTS Before considering the applications of equilibrium constants, let us summarise the important features of equilibrium constants as follows: &
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Predicting the Extent of a Reaction The numerical value of the equilibrium constant for a reaction indicates the extent of the reaction.But it is important to note that an equilibrium constant
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Predicting the Direction of the Reaction The equilibrium constant helps in predicting the direction in which a given reaction will proceed at any stage.For this purpose, we calculate the react
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Calculating Equilibrium Concentrations In case of a problem in which we know the initial concentrations but do not know any of the equilibrium concentrations, the following three steps shall b
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RELATIONSHIP BETWEEN EQUILIBRIUM CONSTANT K, REACTION QUOTIENT Q AND GIBBS ENERGY G The value of Kc for a reaction does not depend on the rate of the reaction. However, as
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FACTORS AFFECTING EQUILIBRIA One of the principal goals of chemical synthesis is to maximise the conversion of the reactants to products while minimizing the expenditure of ener
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Effect of Concentration – An experiment This can be demonstrated by the following reaction: Fe3+(aq)+ SCN–(aq)[Fe(SCN)]2+(aq) (7.24) yellow colourless&n
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Effect of Pressure Change A pressure change obtained by changing the volume can affect the yield of products in case of a gaseous reaction where the total number of moles of gaseous reactants
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Effect of Temperature Change Whenever an equilibrium is disturbed by a change in the concentration, pressure or volume, the composition of the equilibrium mixture changes because the reac
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Effectof a Catalyst A catalyst increases the rate of the chemical reaction by making available a new low energy pathway for the conversion of reactants to products.It increases the rate o
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IONIC EQUILIBRIUM IN SOLUTION Under the effect of change of concentration on the direction of equilibrium, you have incidently come across with the following equilibrium which involves io
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ACIDS,BASES AND SALTS Acids, bases and salts find widespread occurrence in nature.Hydrochloric acid present in the gastric juice is secreted by the lining of our stomach in a significant amount of
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Arrhenius Concept of Acids and Bases According to Arrhenius theory, acids are substances that dissociates in water to give hydrogen ions H +(aq) and bases are substances that produce hydroxyl
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The Bronsted-Lowry Acids and Bases The Danish chemist, Johannes Brönsted and the English chemist, Thomas M. Lowry gave a more general definition of acids and bases. According to Brön
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Lewis Acids and Bases G.N. Lewis in 1923 defined an acid as a species which accepts electron pair and base which donates an electron pair. As far as bases are concerned, ther
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IONIZATIONOF ACIDS AND BASES Arrhenius concept of acids and bases becomes useful in case of ionization of acids and bases as mostly ionizations in chemical and biological systems oc
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The Ionization Constant of Water and its Ionic Product Some substances like water are unique in their ability of acting both as an acid and a base.We have seen this in case of water
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The pH Scale Hydronium ion concentration in molarity is more conveniently expressed on a logarithmic scale known as the pH scale. The pH of a solution is defined as the negative logarithm to b
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Ionization Constants of Weak Acids Consider a weak acid HX that is partially ionized in the aqueous solution. The equilibrium can be expressed by: HX(aq) + H2O(l) H3O+(aq) + X–(a
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Ionization of Weak Bases The ionization of base MOH can be represented by equation: MOH(aq)M+(aq) + OH–(aq) In a weak base there is partial ionization
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Relation between Ka and Kb As seen earlier in this chapter, Ka and Kb represent the strength of an acid and a base,respectively. In case of a conjugate acid-base pair, they ar
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Di-and Polybasic Acids and Di-and Polyacidic Bases Some of the acids like oxalic acid, sulphuric acid and phosphoric acids have more than one ionizable proton per molecule of the acid.
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Factors Affecting Acid Strength Having discussed quantitatively the strengths of acids and bases, we come to a stage where we can calculate the pH of a given acid solution. But, th
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Common Ion Effect in the Ionization of Acids and Bases Consider an example of acetic acid dissociation equilibrium represented as: CH3COOH(aq)H+(aq) + CH3COO&ndas
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Hydrolysis of Salts and the pH of their Solutions Salts formed by the reactions between acids and bases in definite proportions, undergo ionization in water. The cations/anions formed&n
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BUFFER SOLUTIONS Many body fluids e.g., blood or urine have definite pH and any deviation in their pH indicates malfunctioning of the body. The control of pH is also very important in ma
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SOLUBILITY EQUILIBRIA OF SPARINGLY SOLUBLE SALTS We have already known that the solubility of ionic solids in water varies a great deal. Some of these (like calcium chlor
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Solubility Product Constant Let us now have a solid like barium sulphate in contact with its saturated aqueous solution. The equilibrium between the undisolved solid and the ions in a satura
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Common Ion Effect on Solubility of Ionic Salts It is expected from Le Chatelier’s principle that if we increase the concentration of any one of the ions, it should combine with the ion of i
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What are these structures? These structures look similar to each other. Together they form a big structure like an onion bulb! We find from this activity that onion bulbs of different sizes have si
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Objects around us We have seen that our food and clothes have so much variety in them. Not just food and clothes, there is such a vast variety of objects everywhere. We see around us, a chair, a
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Activity 2 (Objects made of different material) Let us collect as many objects as possible, from around us. Each of us could get some everyday objects from home and we could also col
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Properties of Materials Have you ever wondered why a tumbler is not made with a piece of cloth? Recall our experiments with pieces of cloth in Chapter 3 and also keep in mind that we gene
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Hardness When you press different materials with your hands, some of them may be hard to compress while others can be easily compressed. Take a metal key and try to scratch with it, the surface of
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Soluble or Insoluble? Activity 4 Collect samples of some solid substances such as sugar, salt, chalk powder, sand, and sawdust. Take five glasses or beakers. Fill each one of them about two-thir
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Soluble or Insoluble? Activity 4 Collect samples of some solid substances such as sugar, salt, chalk powder, sand, and sawdust. Take five glasses or beakers. Fill each one of them about two-thir
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Soluble or Insoluble? Activity 4 Collect samples of some solid substances such as sugar, salt, chalk powder, sand, and sawdust. Take five glasses or beakers. Fill each one of them about two-thir
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Objects may float or sink in water While doing Activity 4, you might have noticed that the insoluble solids separated out from water. You may have also noticed this with some liquids in Activity 5.
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Transparency You might have played the game of hide and seek. Think of some places where you would like to hide so that you are not seen by others. Why did you choose those places? Would you have t
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Before you read This is a story about a thoughtful and loving son. He works hard to fulfil his parents’ wishes and gets some unexpected help. Taro’s Reward (Lesson video) 1. A you
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5. Then suddenly Taro stopped chopping. What was that sound he heard? Could it be, could it possibly be rushing water?Taro could not remember ever seeing or hearing a rushing stream in tha
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9. That evening there was a long procession of visitors to the woodcutter’s house. Each man heard the story of the waterfall, and took a sip of the saké. In less than an hour the pi
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Introduction of separation of substances In our daily life, there are many instances when we notice a substance being separated from a mixture of materials. Tea leaves are separated from the l
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METHODS OF SEPARATION We will discuss some simple methods of separating substances that are mixed together. You may come across some of these methods being used in day-to-day activities.
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Threshing You must have seen bundles of wheat or paddy stalks lying in fields after harvesting the crop. Stalks are dried in the sun before the grain is separated from them. Each stalk has many gra
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Winnowing Activity-3 Make a mixture of dry sand with sawdust or powdered dry leaves. Keep this mixture on a plate or a newspaper. Look at this mixture carefully. Can the two differen
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Sieving Sometimes, we may wish to prepare a dish with flour. We need to remove impurities and bran that may be present in it. What do we do? We use a sieve and pour the flour into it (Fig. 5.6).
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Sedimentation, Decantation, and Filtration Sedimentation and Decantation Sometimes, it may not be possible to separate components of a mixture by winnowing and handpicking. For example, there ma
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Evaporation Activity 6 Add two spoons of salt to water in another beaker and stir it well. Do you see any change in the colour of water? Can you see any salt in the beaker, after stir
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Use of more than one method of separation Evaporation and Condensation We have studied some methods for separation of substances from their mixtures. Often, one method is not sufficient to separ
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Can water dissolve any amount of a substance? saturated solutions In chapter 4, we found that many substances dissolve in water and form a solution. We say that these substances are soluble in w
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Activity 10 ( Dissolution of different substances) Take two glasses and pour half a cup of water in each of them. Add a teaspoon of salt to one glass and stir till the salt dissolves. Go on adding
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Before you read Do you feel you know your parents better now than when you were much younger? Perhaps you now understand the reasons for some of their actions that used to upset you earlier. Thi
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4. On Sunday afternoons Grandmother sent her down to the drawing-room to have a “nice talk with Father and Mother”. But the little girl always found Mother reading and Father stretch
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7. Crying too much to explain, she lay in the shadowed room watching the evening light make a sad little pattern on the floor. Then Father came into the room w
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10. “What’ll I do if I have a nightmare ?” she asked. “I often have nightmares and then Grannie takes me into her bed—I can’t stay in the dark&mda
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THE ANT AND THE CRICKET - AESOP (Poet) Before you read A fable is a story, often with animals as characters, that conveys a moral. This poem about an ant and a cricket contains an idea of far-re
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THE ANT AND THE CRICKET - AESOP (Poet) Before you read A fable is a story, often with animals as characters, that conveys a moral. This poem about an ant and a cricket contains an idea of far-re
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Before you read Activity: There are some dates or periods of time in the history of the world that are so significant that everyone knows and remembers them. The story you will read mentions one
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PART II Dear Connie, I write to you in a much happier frame of mind because something wonderful has just happened that I must tell you about at once. We were all standing in
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PART-III I folded the letter again and slipped it carefully back into its envelope. I kept awake all night. By morning I knew what I had to do. I drove into Bridport, just a few mile
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Before you read The Tsunami Part I A tsunami is a very large and powerful wave caused by earthquakes under the sea. On 26 December 2004, a tsunami hit Thailand and parts of India such as the
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STORY – THE TSUNAMI Part I ( Lesson Summary ) These stories are all from the Andaman and Nicobar archipelago. Ignesious was the manager of a cooperative society in Katchall.
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Part II Now here is a story from Thailand. The Smith family from South-East England were celebrating Christmas at a beach resort in southern Thailand. Tilly Smith was a ten-year-old sc
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Part III Before the giant waves slammed into the coast in India and Sri Lanka, wild and domestic animals seemed to know what was about to happen. They fled to safety. According to eyewitness accoun
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Before You Read Here are some pictorial glimpses of the history of our country from 1757 to 1857. These pictures and ‘speech bubbles’ will help clarify your understanding of the conditi
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2. The Company’s conquests (1757-1849)
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3. British Rule
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4. Ram Mohan Roy (1772 - 1833)
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5. Oppression ( 1765 - 1835 )
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6. Dissatisfaction ( 1835 - 56 )
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7. The Sparks (1855 - 57)
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8. Revolt ( 1857 )
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9. The Fight For Freedom ( 1857 ) Oral Comprehension Check 1. Look at picture 1 and recall the opening lines of the original song in Hindi. Who is the singer? Who else do you see i
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Before you read Do you have a good memory? Has your memory ever played any tricks on you? Forgetfulness often puts you in a tight spot. But forgetting a part of your life completely may drive yo
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PART-II Bepin Babu’s car was safely parked in Bertram Street by the Lighthouse Cinema. He told the driver as he got into the car, “Just drive by the Ganga, will you, Sitaram.” Dri
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PART-III After lunch-time, Bepin Babu realised that he couldn’t possibly carry on sitting at his desk and working. This had never happened in the twenty-five years he had been with the firm.
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PART-IV Getting off the train at Ranchi the next morning, he realised at once that he had never been there before. He came out of the station, took a taxi, and drove around the town for a while.
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Before you read Major H.P.S. Ahluwalia was a member of the first successful Indian expedition to Mount Everest in 1965. How did he feel when he stood on the highest point in the world? Let us hear
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Consider a typical climb, towards the summit on the last heights. You are sharing a rope with another climber. You firm in. He cuts the steps in the hard ice. Then he belays and you inch your way up.
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Before you read Often, instead of rushing to the doctor to treat a small cut or burn, we find quick and effective cures using things available at home. Can you think of some such ‘home remedi
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PART-II Jody gave himself over to thoughts of the fawn. They passed the abandoned clearing. He said, “Cut to the north, Mill-wheel. It was up here at Pa got bitten by the snake and killed
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PART-III Movement directly in front of him startled him so that he tumbled backward. The fawn lifted its face to his. It turned its head with a wide, wondering motion and shook him through with the
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Before you read This is the story of a meeting between two extraordinary people, both of them ‘disabled’, or ‘differently-abled’ as we now say. Stephen Hawking is one of the
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Before you, like a lantern whose walls are worn so thin you glimpse only the light inside, is the incandescence of a man. The body, almost irrelevant, exists only like a case made of shadows. So that
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Before you read Do you know what a diary is? It is a record of personal experiences written day after day over a long period of time. You can also use a diary to note down things you plan to do imm
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Part II August 2 All night the rain has been drumming on the corrugated tin roof. There has been no storm, no thunder, just the steady swish of a tropical downpour. It helps me to lie awake; at
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Before you read Seen from a distance, hilltops and huge rocks seem to assume various shapes. They may resemble an animal or a human figure. People attribute stories to these shapes. Some stories co
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Part II The years went on, and Ernest grew to be a young man. He attracted little notice from the inhabitants of the valley. They saw nothing remarkable in his way of life, except that, when the la
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Before you read Many years passed. Ernest was now a man of middle age. To his neighbours, who never suspected that he was anything more than an ordinary and familiar face, he was only a humble and
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At the hour of sunset, as had long been his custom, Ernest was to speak to a group of neighbours in the open air. Together he and the poet went to the meeting place, arm in arm. From there could be se
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Before you read A king has three questions and he is seeking answers to them. What are the questions? Does the king get what he wants? STORY – THREE QUESTIONS – LEO TOLSTOY (Aut
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PART - II The king turned round and saw a bearded man running towards them. His hands were pressed against his stomach, from which blood was flowing. When he reached the king he fainted a
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Before you read Mridu is a young girl growing up in Madras (now called Chennai) with Tapi, her grandmother, and Thatha, her grandfather. One afternoon Tapi takes her to her aunt Rukku Manni’s
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Part II Mridu crept up to the window. Lalli was sitting a little distance away, awkwardly holding her violin and bowstring, her elbows jutting out and her eyes glazed with c
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A House, A Home - LORRAINE M. HALL Poem What is the difference between a house and a home? Discuss it with your partner. Then read the poem. What is a house? It’s brick and st
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Before you read We shall now read about a young German civil servant who took the world by storm about a hundred years ago. In the summer of 1905, the 26-year-old published in quick succession four
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6. Einstein was highly gifted in mathematics and interested in physics, and after finishing school, he decided to study at a university in Zurich. But science wasn’t the only th
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12. Einstein’s new personal chapter coincided with his rise to world fame. In 1915, he had published his General Theory of Relativity, which provided a new interpretation of gra
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Before you read “God may have taken her hearing but he has given her back something extraordinary. What we hear, she feels — far more deeply than any of us. That is why she expresses mu
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6. It is intriguing to watch Evelyn function so effortlessly without hearing. In our two-hour discussion, she never missed a word.“Men with bushy beards give me trouble,” she la
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Before you read Think of the shehnai and the first thing you’ll probably imagine is a wedding or a similar occasion or function. The next would probably be Ustad Bismillah Khan, the shehnai
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5. The young boy took to music early in life. At the age of three when his mother took him to his maternal uncle’s house in Benaras (now Varanasi), Bismillah was fascinated watching
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10. National awards like the Padmashri, the Padma Bhushan, and the Padma Vibhushan were conferred on him. 11. In 2001, Ustad Bismillah Khan was awarded India’s highest
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Before you read The story we shall read is set in the future when books and schools as we now know them will perhaps not exist. How will children study then? The diagram below may give you some ide
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5. The Inspector had smiled after he was finished and patted Margie’s head. He said to her mother, “It’s not the little girl’s fault, Mrs. Jones. I think the g
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The Quarrel - ELEANOR FARJEO The Quarrel It is common for brothers and sisters to quarrel, although sometimes they may not even be able to say why they quarrel. But how long do such quarr
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Illustration 3.3: Calculate the number of moles for the following: i. 52 g of He (finding mole from mass) ii. 12.044 \(\times\) 1023 number of He atoms (finding mole from the
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Introduction to Heat In Chapter 3 you learnt that woollen clothes are made from animal fibres. You also know that cotton clothes are made from plant fibres. We wear woollen clothes during wint
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Hot and Cold In our day-to-day life, we come across a number of objects. Some of them are hot and some of them are cold. Tea is hot and ice is cold. List some objects you use commonly in Table 4.1.
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Measuring Temperature Have you seen a thermometer? Recall that when you or someone else in your family had a fever, the temperature was measured by a thermometer. The thermometer that mea
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Activity 4.2: Reading a Thermometer Let us learn how to read a thermometer. First, note the temperature difference indicated between the two bigger marks. Also, note down the number of division
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Activity 4.3: Measure the body temperature of some of your friends (at least 10) with a clinical thermometer. Record your observations as in Table 4.2. &nbs
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Laboratory Thermometer How do we measure the temperature of other objects? For this purpose, there are other thermometers. One such thermometer is known as the laboratory thermometer. The
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Activity 4.4: Take some tap water in a beaker or a mug. Dip the thermometer in water so that the bulb is immersed in water but does not touch the bottom or the sides of the container. Hold the ther
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TRANSFER OF HEAT You might have observed that a frying pan becomes hot when kept on a flame. It is because the heat passes from the flame to the utensil. When the pan is removed from the fire, it s
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Conduction - Activity 4.6: Take a rod or flat strip of metal, say aluminium or iron. Fix a few small wax pieces on the rod. These pieces should be at nearly equal distances (Fig. 4.7).
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Conductors and Insulators Activity 4.7: Heat water in a small pan or a beaker. Collect some articles such as a steel spoon, plastic scale, pencil, and divider. Dip one end of each of these article
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Convection Activity 4.8: ( Convection in water ) Take a round bottom flask (if the flask is not available, a beaker can be used). Fill it two-thirds with water. Place it on a tripod,
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Sea Breeze, Land Breeze and Radiation The people living in the coastal areas experience an interesting phenomenon. During the day, the land gets heated faster than the water. The air over the land
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KINDS OF CLOTHES WE WEAR IN SUMMER AND WINTER You know that in summer we prefer light-coloured clothes and in winter we usually wear dark-coloured clothes. Why is it so? Let us find out
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Before you read Now read this humorous story about a doctor, a snake, and a mirror. written by VAIKOM MUHAMMAD BASHEER and translated from Malayalam by V.Abdulla. Activ
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5. I took a close look at my face in the mirror. I made an important decision — I would shave daily and grow a thin moustache to look more handsome. I was after all a bachelor a
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9. At my slightest movement the snake would strike me! Death lurked four inches away. Suppose it struck, what was the medicine I had to take? There were no medicines in the room. I was but
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MY CHILDHOOD Before you read A.P.J. Abdul Kalam, whose projects in space, defense, and nuclear technology guided India into the twenty-first century, became our eleventh President in 2002.
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3. The Second World War broke out in 1939 when I was eight years old. For reasons I have never been able to understand, a sudden demand for tamarind seeds erupted in the market. I use
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6. One day when I was in the fifth standard at Rameswaram Elementary School, a new teacher came to our class. I used to wear a cap that marked me as a Muslim, and I always sat in the
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9. One day, he invited me to his home for a meal. His wife was horrified at the idea of a Muslim boy being invited to dine in her ritually pure kitchen. She refused to serve me in her
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Before you read Read this description of how the author and his friends pack. It is an extract from Three Men in a Boat, written by JEROME K. JEROME. Activity: * 
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4. However, I did not say anything but started packing. It seemed a longer job than I had thought it was going to be, but I got the bag finished at last, and I sat on it and
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7. When I had finished, George asked if the soap was in. I said I didn’t care a hang whether the soap was in or whether it wasn’t, and I slammed the bag shut and stra
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10. They upset salt over everything, and as for the butter! I never saw two men do more with one-and-two pence worth of butter in my whole life than they did. After George had go
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13. He came and sat down on things, just when they were wanted to be packed; and he laboured under the fixed belief that, whenever Harris or George reached out their hand fo
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Before you read REACH FOR THE TOP - SANTOSH YADAV Activity: Think for a while and make a list of three to five persons you idolise, or admire very much for their achievements. Your idols may
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4. A marriage as early as that was the last thing on her mind. She threatened her parents that she would never marry if she did not get a proper education. She left home and got herself enr
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7. Thereafter, Santosh went on an expedition every year. Her climbing skills matured rapidly. Also, she developed a remarkable resistance to cold and altitude. Equipped with an iron will, p
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Before you read MARIA SHARAPOVA Activity: 1. A Russian girl, Maria Sharapova, reached the summit of women’s tennis when she was barely eighteen. As you read about her, see if
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3. “I used to be so lonely,” Maria Sharapova recalls. “I missed my mother terribly. My father was working as much as he could to keep my tennis training going. So, he
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7. While her journey from the frozen plains of Siberia to the summit of women’s tennis has touched the hearts of tennis fans, for the youngster herself there appears to be no room for
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Before you read Sloth bears inhabit forested areas, including the tropical rain forests of India and grasslands at lower elevations. Sloth bears have very shaggy hair and long muzzles. Using their
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5. We put it in one of the gunny bags we had brought and when I got back to Bangalore I duly presented it to my wife. She was delighted! She at once put a coloured ribbon around its ne
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9. Out came his medical books, and a feverish reference to index began: “What poison did you say, sir?” “Barium carbonate”. “Ah yes—B—Ba—Bari
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13. Then my son and I advised my wife, and friends advised her too, to give Baba to the zoo at Mysore. He was getting too big to keep at home. After some weeks of such advice, she at last c
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17. For the next three hours she would not leave that cage. She gave him tea, lemonade, cakes, ice cream, and whatnot. Then ‘closing time’ came and we had to leave. My wife
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21. Once home, a squad of coolies was engaged for special work in our compound. An island was made for Baba. It was twenty feet long and fifteen feet wide and was surrounded by a dry pit, o
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Before you read KATHMANDU Do you like travelling? The writer, Vikram Seth, enjoys it very much. In his book, Heaven Lake, he describes a long journey from China to India, via Tibet and Nepal.
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3. At the Baudhanath stupa, the Buddhist shrine of Kathmandu, there is, in contrast, a sense of stillness. Its immense white dome is ringed by a road. Small shops stand on its outer e
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6. I look at the flute seller standing in a corner of the square near the hotel. In his hand is a pole with an attachment at the top from which fifty or sixty bansuris protrude in all
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x| thou laxzke dh Hkk"kk gSA – lw;Zdkar f=ikBh ^fujkyk* ;fn x| dfo;ksa dh dlkSVh gS rks fucaèk x| dh dlkSVh gSA Hkk"kk dh iw.kZ 'kfDr dk fodkl fuca/kksa esa
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Activity 8.6: * Measure the time it takes you to walk from your house to your bus stop or the school. * If you consider that your average walking speed is 4 kmh–1, e
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Activity 8.8: * In your everyday life you come across a range of motions in which a. acceleration is in the direction of motion,  
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Activity 8.11: ( Motion in a circular path ) * Take a piece of thread and tie a small piece of stone at one of its ends. Move the stone to describe a circular path with consta
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Illustration 9.1 : A constant force acts on an object of mass 5 kg for a duration of 2 s. It increases the object’s velocity from 3 ms–1 to 7 ms-1. Find the magnitude o
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Activity 9.4: * Request two children to stand on two separate carts as shown in Fig. 9.13. * Give them a bag full of sand or some other heavy object. Ask them to pla
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Activity 9.5: ( Balloon Rocket ) * Take a big rubber balloon and inflate it fully. Tie its neck using a thread. Also using adhesive tape, fix a straw on the surface of this balloon.
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Illustration 9.7: A girl of mass 40 kg jumps with a horizontal velocity of 5 ms-1 onto a stationary cart with frictionless wheels. The mass of the cart is 3 kg. What is her velocity as the cart sta
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CONSERVATION LAWS All conservation laws such as conservation of momentum, energy, angular momentum, charge, etc. are considered to be fundamental laws in physics. These are based on observatio
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Beauty – E-YEH-SHURE What is beauty? Try to describe what beauty is, or list some of the things or persons you think are beautiful. Now let us read a poem on beauty. Beau
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The Tiny Teacher Though so very small, the ant is unbelievably intelligent and hard-working. Among the various kinds, the commonest ant is black or red. Ants live in comfortable homes ca
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There are many kinds of ants. The commonest among them are the black or red ones. We have seen them since we were children, but haven’t paid enough attention to them. Where do they live? In
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They spend most of their time searching for food. Some rooms serve as storehouses for this food. Soldiers have separate barracks. No worker has ever tried to live in a soldier’s house; no soldie
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The queen is the mother of the entire population of the colony. It lives for about fifteen years. It has a pair of wings, but bites them off after its ‘wedding’ flight. This flight takes p
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The greenfly is the ants’ cow. The ants train it to give honeydew (like milk) with a touch of their antennae. They milk it just as we milk the cow. Have humans learned as much as ants have?
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How the Camel got his hump ( Lesson Video ) The world had just begun, and the animals we're working for humans. There was one lazy animal that did nothing and said nothing but ‘Humph&r
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Lesson Video Presently the Ox came to him, with the yoke on his neck, and said, “Camel, O Camel, come and plough like the rest of us.” “Humph!” said the Camel, and the Ox
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Lesson Video “Djinn of All Deserts,” said the Horse, “is it right for any one to be idle?” “Certainly not,” said the Djinn. “Well,” said th
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Lesson Video The Djinn remonstrated with the camel, who said “Humph”. The camel’s beautiful back suddenly grew a lump, which was the camel’s hump. The Djinn assured th
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Lesson Video “How can I,” said the Camel, “with this humph on my back?” ‘‘That has a purpose,” said the Djinn, “all because you missed 
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LOCATION AND SIZE ( View Mind Map ) India is one of the ancient civilizations in the world. It has achieved multifaceted socio-economic progress during the last five decad
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Size The landmass of India has an area of 3.28 million square km. India’s total area accounts for about 2.4 percent of the total geographical area of the world. From Figure 1.2
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Latitudes and Longitudes Look at Figure 1.3 and note that the latitudinal and longitudinal extent of the mainland is about 30°. Despite this fact, the east-west extent appears to be smaller tha
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INDIA AND THE WORLD The Indian landmass has a central location between East and West Asia. India is a southward extension of the Asian continent. The trans-Indian Ocean routes, which
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NEIGHBOURS OF INDIA India occupies an important strategic position in South Asia. India has 28 states and nine Union Territories (Figure 1.5). Figure 1.5: India and Adjacent C
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Major physiographic divisions The physical features of India can be grouped under the following physiographic divisions (Figure 2.1): Figure 2.1: Relief
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THE HIMALAYAN MOUNTAINS The Himalayas The Himalayas, geologically young and structurally fold mountains stretch over the northern borders of India. These mountain ranges run
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THE HIMALAYAN MOUNTAINS Himachal or Lesser Himalaya The range lying to the south of the Himadri forms the most rugged mountain system and is known as Himachal or lesser Himal
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THE HIMALAYAN MOUNTAINS The Shiwaliks The outermost range of the Himalayas is called the Shiwaliks. They extend over a width of 10-50 Km and have an altitude varying bet
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THE HIMALAYAN MOUNTAINS Regions from East to West Besides the longitudinal divisions, the Himalayas have been divided on the basis of regions from west to east. These divisio
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THE NORTHERN PLAIN The northern plain has been formed by the interplay of the three major river systems, namely — the Indus, the Ganga, and the Brahmaputra along with their tributaries.
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DIVISION OF THE NORTHERN PLAIN The Northern Plain is broadly divided into three sections. The Western part of the Northern Plain is referred to as the Punjab Plains. Formed by the Indus and its tri
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RELIEF FEATURES OF NORTHERN PLAIN The northern plains are generally described as flat land with no variations in its relief. It is not true. These vast plains also have diverse relief features. Acc
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THE PENINSULAR PLATEAU The Peninsular plateau is a tableland composed of the old crystalline, igneous and metamorphic rocks. It was formed due to the breaking and drifting of the Gondwana land and
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THE CENTRAL HIGHLANDS The part of the Peninsular plateau lying to the north of the Narmada river, covering a major area of the Malwa plateau, is known as the Central Highlands. The Vindhyan range i
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THE DECCAN PLATEAU The Deccan Plateau is a triangular landmass that lies to the south of the river Narmada. The Satpura range flanks its broad base in the north, while the Mahadev, the Ka
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THE Western and Eastern Ghats The Western Ghats and the Eastern Ghats mark the western and the eastern edges of the Deccan Plateau respectively. The Western Ghats lie parallel t
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DISTINCT FEATURES One of the distinct features of the Peninsular plateau is the black soil area known as Deccan Trap. This is of volcanic origin, hence, the rocks are igneous. Actually, t
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THE INDIAN DESERT The Indian desert lies towards the western margins of the Aravali Hills. It is an undulating sandy plain covered with sand dunes. This region receives very low rainfall below 150
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THE COASTAL PLAINS The Peninsular plateau is flanked by a stretch of narrow coastal strips, running along the Arabian Sea on the west and the Bay of Bengal on the east. The western coast, sandwiche
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LAKSHADWEEP ISLANDS You have already seen that India has a vast mainland. Besides this, the country has two groups of islands. Can you identify these island groups? Figure 2.9: An Islan
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ANDAMAN AND NICOBAR ISLANDS Now you see the elongated chain of islands located in the Bay of Bengal extending from north to south. These are Andaman and Nicobar Islands. They are bigger in size and
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HIGHLIGHTS A detailed account of the different physiographic units highlights the unique features of each region. It would, however, be clear that each region complements the other and ma
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Chemistry deals with varieties of matter and changes of one kind of matter into the other. Transformation of matter from one kind into another occurs through the various types of reactions. One import
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CLASSICAL IDEA OF REDOX REACTIONS – OXIDATION AND REDUCTION REACTIONS Originally, the term oxidation was used to describe the addition of oxygen to an element or a compound. Because
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PROBLEM 1 In the reactions given below, identify the species undergoing oxidation and reduction: 1. H2S (g) + Cl2 (g) \(\to\) 2 HCl (g) + S (s) 2. 3Fe3O4 (s) + 8 Al (s) \(\to\)
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REDOX REACTIONS IN TERMS OF ELECTRON TRANSFER REACTIONS We have already learnt that the reactions (g) 2NaCl (s) \(\to\)2Na(s) + Cl2 (8.12) 4Na(s) +
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PROBLEM 2 Justify that the reaction : 2 Na(s) + H2(g) \(\to\) 2 NaH (s) is a redox change. SOLUTION Since in the above reaction the compound form
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Competitive Electron Transfer Reactions Place a strip of metallic zinc in an aqueous solution of copper nitrate as shown in Fig. 8.1, for about one hour. Fig. 8
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OXIDATION NUMBER A less obvious example of electron transfer is realised when hydrogen combines with oxygen to form water by the reaction: 2H2(g) + O2 (g) \(\to\) 2H2O (l) &
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PROBLEM 3 Using Stock notation, represent the following compounds :HAuCl4, Tl2O, FeO, Fe2O3, CuI, CuO, MnO and MnO2. SOLUTION By applying various rules of calcul
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1. Combination reactions A combination reaction may be denoted in the manner: A + B \(\to\) C Either A and B or both A and B must be in the elemental form for such a reaction to be a red
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3. Displacement reactions In a displacement reaction, an ion (or an atom) in a compound is replaced by an ion (or an atom) of another element. It may be denoted as: X + YZ&nb
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4. Disproportionation reactions Disproportionation reactions are a special type of redox reactions. In a disproportionation reaction an element in one oxidation state is simultaneously ox
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PROBLEM 5 Which of the following species, do not show disproportionation reaction and why? ClO , ClO\(% MathType!MTEF!2!1!+- % feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn
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Balancing of Redox Reactions Two methods are used to balance chemical equations for redox processes. One of these methods is based on the change in the oxidation number of re
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IN THE KINGDOM OF FOOLS It is believed that fools are so dangerous that only very wise people can manage them. Who are the fools in this story? What happens to them? &n
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IN THE KINGDOM OF FOOLS But the disciple wouldn’t listen to the guru’s wisdom. He wanted to stay. The guru finally gave up and said, “Do what you want. I&rsquo
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IN THE KINGDOM OF FOOLS When the merchant arrived, the king questioned him. “What’s your name?” “Such and Such, Your Highness.” “Were you at home when t
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IN THE KINGDOM OF FOOLS It has fallen on a poor burglar and killed him. You’ve killed an innocent man. You’ll have to be punished.” She thought for a
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IN THE KINGDOM OF FOOLS The goldsmith named the merchant, and he was none other than the original owner of the house whose wall had fallen. Now justice had come full circle, thought the king, back
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IN THE KINGDOM OF FOOLS “What have I done wrong? I’m innocent. I’m a sanyasi!” he cried. “That may be true. But it’s the royal decree that we should find a man f
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IN THE KINGDOW OF FOOLS When the disciple heard this, he understood and began to clamour, “Me first! You brought me here first! Put me to death first, not him!”
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IN THE KINGDOW OF FOOLS When the bodies were taken down to be thrown to crows and vultures the people panicked. They saw before them the dead bodies of the king and the minister. The city was i
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THE HAPPY PRINCE The Happy Prince was a beautiful statue. He was covered with gold, he had sapphires for eyes, and a ruby in his sword. Why did he want to part with all the gold that he had, and hi
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THE HAPPY PRINCE Then another drop fell. “What is the use of a statue if it cannot keep the rain off ?” he said. “I must look for a good chimney pot,” and he determined t
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THE HAPPY PRINCE “I am waited for in Egypt,” said the swallow. “My friends are flying up and down the Nile, and talking to the large lotus flowers. Soon they will go to sleep.&rdq
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THE HAPPY PRINCE When the moon rose he flew back to the Happy Prince. “Have you any commissions for Egypt?” he cried. “I am just starting.” “Swallow,
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THE HAPPY PRINCE He ordered the swallow to pluck out one of them and take it to the playwright. “He will sell it to the jeweller, and buy firewood, and finish his play,” he said. &ld
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THE HAPPY PRINCE Pluck out my other eye, and give it to her, and her father will not beat her.” “I will stay with you one night longer,” said the swallow, “but
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THE HAPPY PRINCE Then the snow came, and after the snow came the frost. The streets looked as if they were made of silver. Everybody went about in furs, and the little boys wore scarlet c
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THE HAPPY PRINCE So they pulled down the statue of the Happy Prince. “As he is no longer beautiful he is no longer useful,” said the Art Professor at the University. Then they me
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WEATHERING THE STORM IN ERSAMA The cyclone that hit Orissa in October 1999 killed thousands of people and devastated hundreds of villages. For two dreadful nights Prashant, a yo
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WEATHERING THE STORM IN ERSAMA At places it was waist deep, and progress was slow. At several points, he lost the road and had to swim. After some distance, he was relieved to find tw
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WEATHERING THE STORM IN ERSAMA By the next morning, as he took in the desperate situation in the shelter, he decided to get a grip over himself. He sensed a deathly grief settling upon the 2500 str
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WEATHERING THE STORM IN ERSAMA Then they deputed the children to lie in the sand left by the waters around the shelter with these utensils on their stomachs, to communicate to the passing heli
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THE LAST LEAF It is autumn. The wind is blowing hard and it is raining heavily. All the leaves on an ivy creeper have fallen, except one. Why doesn’t the last leaf fall? SUE and Johnsy, tw
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THE LAST LEAF “What is it, dear?” Sue asked. “Six,” whispered Johnsy. “They are falling faster now. Three days ago there were almost a hundred leaves. There are onl
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THE LAST LEAF “All right,” said Johnsy. “Finish your painting soon for I want to see the last leaf fall. I’m tired of waiting. I have to die, so let me go away pea
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THE LAST LEAF “Oh!” Sue exclaimed as she looked at the vine creeper. “Look, there is still one leaf on the creeper. It looks quite green and healthy. In spite of th
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A HOUSE IS NOT A HOME This story reflects the challenges of being a teenager, and the problems of growing up. How does the author overcome his problems? MY first year of high
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A HOUSE IS NOT A HOME By the time we made our way outside, the whole roof was engulfed in flames and it was spreading quickly. I ran to the neighbours to call the fire department, while I watched m
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A HOUSE IS NOT A HOME He quickly took her over to the truck and put an oxygen mask on her. I ran over and hugged her. All those times I ever argued with her and hated her vanished at the thought of
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A HOUSE IS NOT A HOME When I walked through what used to be my house after school that day, I was shocked to see how much damage there was — whatever hadn’t burned was destroy
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A HOUSE IS NOT A HOME In that instant, I finally breathed a sigh of relief and thought for the first time that things were going to be okay. I made friends that day. A month
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THE ACCIDENTAL TOURIST They say that the world today is a small place because travel has become easy, but not everybody finds it easy to travel. Here, the author reflects humorously his e
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THE ACCIDENTAL TOURIST I watched dumbstruck as a hundred carefully sorted documents came raining down in a fluttery cascade, coins bounced to a variety of noisy oblivions and the now-lidl
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THE ACCIDENTAL TOURIST On another occasion, I knocked a soft drink onto the lap of a sweet little lady sitting beside me. The flight attendant came and cleaned her up, and brought me a re
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THE ACCIDENTAL TOURIST I amused her for perhaps 20 minutes with a scattering of urbane bons mots, then retired to the lavatory where I discovered that the pen had leaked and that my mouth, chin, to
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THE LOST CHILD A child goes to a fair with his parents. He is happy and excited and wants the sweets and toys displayed there. But his parents don’t buy them for him. Why then does he refuse
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THE LOST CHILD As they neared the village the child could see many other footpaths full of throngs, converging to the whirlpool of the fair, and felt at once repelled and fascinated by the confusio
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THE LOST CHILD There was no reply. He turned to look at his parents. They were not there, ahead of him. He turned to look on either side. They were not there. He looked behind. There was no sign of
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THE LOST CHILD The man headed towards the place where the snake-charmer still played on the flute to the swaying cobra. “Listen to that nice music, child!&rd
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THE ADVENTURES OF TOTO GRANDFATHER bought Toto from a tonga-driver for the sum of five rupees. The tonga-driver used to keep the little red monkey tied to a feeding-trough, and the monkey looked so
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THE ADVENTURES OF TOTO But Grandfather didn’t worry; he seemed pleased with Toto’s performance. “He’s clever,” said Grandfather. “Given time, I’m sure h
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THE ADVENTURES OF TOTO When Toto was finally accepted by Grandmother he was given a comfortable home in the stable, where he had for a companion the family donkey, Nana. On Toto’s first n
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ISWARAN THE STORYTELLER One night Mahendra woke up from his sleep and saw “a dark cloudy form”. He broke out into a cold sweat. Was it a ghost? THE
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ISWARAN THE STORYTELLER He was a bachelor. His needs were simple and he was able to adjust himself to all kinds of odd conditions, whether it was an ill-equipped circuit house o
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ISWARAN THE STORYTELLER “The place I come from is famous for timber,” Iswaran would begin. “There is a richly wooded forest all around. The logs are hauled on to the lorries by el
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ISWARAN THE STORYTELLER The beast looked stunned for a moment; then it shivered from head to foot — and collapsed.” At this point Iswaran would leave the story unfinished,
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ISWARAN THE STORYTELLER He went on to narrate how he sometimes saw ghosts at night. “I am not easily frightened by these things, sir. I am a brave fellow. But one horrible ghost
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ISWARAN THE STORYTELLER But he could only see a sea of darkness with the twinkling lights of the factory miles away. He had always liked to admire the milk-white landscape on full-moon nights. B
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THE BAGGAR What induced the beggar, Lushkoff, to change his ways? Let’s read and find out. “KIND sir, have pity; turn your attention to a poor, hungry m
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THE BEGGAR “This is dishonesty, my dear sir!” he cried angrily. “This is swindling — I shall send the police for you, damn you!” “Sir!” he said, laying
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THE BEGGAR Next he saw the pseudo-teacher seat himself on a log and become lost in thought with his red cheeks resting on his fists. The woman flung down an axe at his feet, spat angrily, and,
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THE BEGGAR Now he would shovel snow, now put the wood-shed in order, now beat the dust out of rugs and mattresses. Every time he received from twenty to forty copecks, and once, even a pair of old
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THE BEGGAR “Thank Heaven! That’s fine! I am delighted for your sake. I am very, very glad, Lushkoff. You see, you are my godson, in a sense. I gave you a push along the righ
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CHILDREN AT WORK Before you read There are many reasons why children have to work. Some help their family make a livelihood. Others, who run away from unhappy homes
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CHILDREN AT WORK Velu put his head down on his knees, feeling miserable and exhausted. He had run away from his village two days ago. For two days he had eaten nothing but some peanuts an
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CHILDREN AT WORK “No need to stare stupidly. What’s your name?” “Velu,” muttered Velu, looking away. “So Mr Velu,” said the girl, looking at his bund
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CHILDREN AT WOR
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CHILDREN AT WORK Velu looked up at the pictures: banians, car tyres, pens, a woman holding a box. The writing was all in English, so he didn’t know what it meant. The girl turned
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If you are not careful, you will soon be counting bars there,” the girl said. What is she referring to? CHILDREN AT WORK “Hopes!” said the girl shaking her thu
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CHILDREN AT WORK Velu stared. This was a canal? Near some puddles of water was a row of the strangest huts he had ever seen. They were built out of all sorts of things — metal sheets, tyres,
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THE SELFISH GIANT I The Giant’s garden was beautiful, and children loved to play in it. The Giant, who was selfish, built a high wall round his lovely garden. Ch
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THE SELFISH GIANT Once a beautiful flower put its head out from the grass, but when it saw the notice-board it was so sorry for the children that it slipped back into the ground again, an
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THE SELFISH GIANT The birds were flying about and twittering with delight, and the flowers were looking up through the green grass and laughing. It was a lovely scene. Only in one corner it was sti
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THE SELFISH GIANT “It is your garden now, little children,” said the Giant, and he took a great axe and knocked down the wall. And when the people were going to market at twelve o&rsquo
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THE SELFISH GIANT One winter morning he looked out of his window as he was dressing. He did not hate the winter now, for he knew that it was merely the Spring asleep, and that the flowers were rest
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THE TREASURE WITHIN Before you read Every child is a potential achiever and is different from other children in her/his style of learning and area of interest. R
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THE TREASURE WITHIN I read a book and I can remember the matter as a photograph but not through my mind. That is how it works. BR: When you were in school and you were
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THE TREASURE WITHIN Now, who would give me admission in another college? I had got admission to Jaihind by influence. So I thought, ‘Okay, I will take French&
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THE TREASURE WITHIN In school, when I was in the second or third standard, one of my teachers, Mrs Gupta, saw my sketches and told me, “See, you are useless in everything else but your sketch
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THE TREASURE WITHIN BR: That is because the personality and skills were there. You were able to find expression in a manner you were comfortable with and you defied every rule so that nobody would
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PRINCESS SEPTEMBER Princess September, like each one of her numerous sisters, receives the gift of a parrot in a golden cage on her father’s birthday. The parrot dies, and by chance a sing
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PRINCESS SEPTEMBER But one day when Princess September went to say good morning to her parrot she found it lying dead at the bottom of its golden cage. She burst into a flood of tears, and noth
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PRINCESS SEPTEMBER The little bird gave her a bow. “Would you care to have me in place of your parrot?” said the little bird. “It’s true that I’m not so pretty to look
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PRINCESS SEPTEMBER The Princesses were vexed at this, and the parrots looked very glum indeed. But Princess September ran through all the rooms of the palace, singing like a lark, whi
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PRINCESS SEPTEMBER
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PRINCES SEPTEMBER The bird suspected nothing and he was so surprised when she carried him over to the cage, popped him in, and shut the door on him that for a moment he could think of nothing to sa
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PRINCESS SEPTEMBER “Don’t be such an old silly,” said September. “I’ve put you in the cage because I’m so fond of you. I know what’s good for you much bett
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PRINCESS SEPTEMBER She opened the door and putting her hand in lifted him out. She gave a sob of relief, for she felt that his little heart was beating still. “Wake up, wake up, little bir
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PRINCESS SEPTEMBER He gave himself another shake. “Good gracious me, how stiff I am,” he exclaimed.Then he opened his wings and flew right away into the blue. But the little P
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THE FIGHT  
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THE FIGH The rocks, however, held the water in the pool, and it did not dry up like the pools in the plains. When Ranji saw the pool, he did not hesitate to get into it. He h
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THE FIGHT “Now — now do you realise — I am a Warrior?” gasped the stranger. “Do you know I am a Fighter?” said Ranji with difficulty. They gave a momen
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THE FIGHT Instead, he stood his ground and scowled at his passing adversary. And the warrior said nothing either but scowled back with equal ferocity. The next day was as hot as the previous
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THE FIGHT He was half hoping that the warrior would have forgotten the challenge, but these hopes were dashed when he saw his opponent sitting, stripped to the waist, on a rock on the other side of
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THE FIGHT “Are you trying to empty the pool?” he asked, as the warrior came to the surface, spouting water like a small whale. “Wasn’t it good?” asked the boy, evid
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THE FIGHT We have got our own cow! Be my friend, and I will make you a pahelwan like me! I know — if you teach me to dive and swim underwater, I will make you a pahelwan! That
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THE OPEN WINDOW &nbs
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THE OPEN WINDOW Framton wondered whether Mrs Sappleton, the lady to whom he was presenting one of the letters of introduction, came into the nice division. “Do you know many of t
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THE OPEN WINDOW “Poor aunt always thinks that they will come back someday, they and the little brown spaniel that was lost with them, and walk in at that window just as they used to do. T
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THE OPEN WINDOW
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THE OPEN WINDOW He made a desperate but only partially successful effort to turn the talk on to a less ghastly topic; he was conscious that his hostess was giving him only a fragment of her attenti
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THE OPEN WINDOW Framton shivered slightly and turned towards the niece with a look intended to convey sympathetic comprehension. The child was staring out through the open window with a d
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JALEBIS I An honest boy is on his way to school carrying money in his pocket to pay the school fees. The sight of crisp, syrupy jalebis in the market excites him and the coins in his poc
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JALEBIS Money is meant to be spent and only they spend it, who like jalebis.” “Look here, you four rupees, I said to them. I am a good boy. Don’t misguide me or it won’t
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JALEBIS After taking a few steps, I loosened my grip. Immediately, the oldest coin said, “Here we are trying to tell you something for your own good and you try to strangle us inste
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JALEBIS Very quickly, boys from the entire neighbourhood assembled in the gali. By that time I was so pleased with my stomach full of jalebis that I got into the mood for some fun. I
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JALEBIS Jalebis I had gobbled up easily enough, but digesting them became another matter. With every breath came a burp, and with every burp, the danger of bringing out a jalebi or two — the
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JALEBIS The elders had warned me never to cross the railway tracks. Fine. The elders had also warned me that one must never eat sweets with one’s fees money. How did this instruction esc
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JALEBIS Then I felt like laughing when it struck me that the tears I was shedding were not tears but drops of jalebi syrup. From the jalebis my thoughts went to the fees, and from fees to Mast
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JALEBIS Forget four rupees, there weren’t even four paise in my bag. Just a few textbooks and notebooks. One pencil. One sharpener. One Id card my Mamu had sent me last Id. I felt like cry
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JALEBIS Then, crawling on my hands and knees, I reached the tree. I tried my best not to let my eyes stray towards the rock. But as I picked up my bag and was about to leave, I had to look onc
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THE COMET 1 I
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THE COMET2 Did you know that India has been the centre of learning since ancient times? How did we come to know about this? There are inscriptions on stones and copper, palm leaf records and o
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BRINGING UP KARI KARI, the elephant, was five months old when he was given to me to take care of. I was nine years old and I could reach his back if I stood on tiptoe. He seemed to remain that high
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BRINGING UP KARI On coming out his skin would be shining like ebony, and he would squeal with pleasure as I rubbed water down his back. Then I would take him by the ear, because
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BRINGING UP KARI I thought somebody was hurting him, so I came down from my tree and ran very fast to the edge of the forest where I had left him, but he was not there. I looked all over, b
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BRINGING UP KARI I found myself going under the water again, but this time I found that the water was not very deep so I sank to the bottom of the river and doubled my feet under me
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BRINGING UP KARI Next day, while I was sitting in the dining-room wondering whether I should take some fruit from the table without my parents’ permission, a long, black thing,
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BRINGING UP KARI That instant the trunk looked like a black snake, and I realised that Kari was the thief. I went to him, pulled him out by the ear and joyously showed my parents that it was K
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BRINGING UP KARI It is, therefore, better to teach him to sit down by saying ‘Dhat’ so that you can climb upon his back, for who would want to carry a ladder around all the time?
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THE DESTERT THOSE of us who live in regions covered with forests and surrounded by hills may find it difficult to imagine what a desert is really like. The popular belief is that it is an endless s
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THE DESERT A desert may be hot like the Thar or cold like Ladakh. But, generally speaking, if a place has little or no water and vegetation, people usually call it a desert.
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THE DESERT All living things need water in order to survive. The few plants and animals that live in deserts have developed the ability to require less water than most plants and animals.
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THE DESERT Camels can do without water for days together. The reason is they sweat very little. We sweat because we must keep our body temperature constant. W
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THE COP AND THE ANTHEM BEFORE YOU READ Have you ever found yourself in a situation in which what happened was the opposite of what you expected? If so, you are familiar with the ‘irony&rsq
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THE COP AND THE ANTHEM Soapy’s hopes for the winter were not very high. He was not thinking of sailing away on a ship. He was not thinking of southern skies, or of the Bay of Naples
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THE COP AND THE ANTHEM He could move from one building to another, and he would be taken care of through the winter. But he liked Blackwell’s Island better. Soapy’s sp
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THE COP AND THE ANTHEM The part of him that would be seen above the table would look all right. The waiter would bring him what he asked for. He began thinking of what he would like to
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THE COP AND THE ANTHEM “Where’s the man that did that?” asked the cop. “Don’t you think that I might have done it?” said Soapy. He was friendly and happy.
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THE COP AND THE ANTHEM When he had finished, he said that he had no money. “Get busy and call a cop,” said Soapy. “And don’t keep a gentleman waiting.” “No
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THA COP AND THE ANTHEM Then he came to another cop standing in front of a big theatre. He thought of something else to try. He began to shout as if he had too much to drink. His voice was as lou
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THE COP AND THE ANTHEM But he had a feeling that he was going to fail again. The cop looked at the two men. “I—” said the umbrella man “— that is &md
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THE COP AND THE ANTHEM There was time. He was young enough. He would find his old purpose in life, and follow it. That sweet music had changed him. Tomorrow he would find work. A man had once o
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GOLU GROWS A NOSE LONG, long ago the elephant had no trunk. He had only a bulgy nose, as big as a boot. He could wiggle it from side to side, but couldn’t pick up th
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GOLU GROWS A NOSE Golu was full of questions. He asked his tall aunt, the ostrich, “Why don’t you ever fly like other birds?” Then he asked his tall uncle, the giraffe, &ldqu
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GOLU GROWS A NOSE The python uncoiled himself from the branch of a tree but said nothing. Golu politely helped him to coil around the branch again and said goodbye to him. Golu moved o
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GOLU GROWS A NOSE Golu sat back on his little haunches and pulled and pulled. The crocodile slipped into the water making it all creamy with great sweeps of his tail, and he also pulled a
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I WANT SOMETHING IN A CAGE MR PURCELL did not believe in ghosts. Nevertheless, the man who bought the two doves, and his strange act immediately thereafter, left him with a distinct sense
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I WANT SOMETHING IN A CAGE Small feet scampered in frantic circles —frightened, bewildered, blindly seeking. Across the shelves pulsed this endless flicker of life. But the customer
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I WANT SOMETHING IN A CAGE Smoke filmed the wintry city and the air was grey with a thick frost. Having completed his usual tasks, Mr Purcell again mounted the high stool, and unfold
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I WANT SOMETHING IN A CAGE The man’s shiny shoes squeaked forward. His suit was cheap, ill-fitting but obviously new. He had a shuttling glance and close-cropped hair. Ignoring Purc
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I WANT SOMETHING IN A CAGE “A bird’s all right.” The customer pointed suddenly to a suspended cage which contained two snowy birds. “Doves? How much for those?&rdq
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I WANT SOMETHING IN A CAGE “They give you five dollars,” laughed the man, “and a cheap suit, and tell you not to get caught again.” Mr Purcell mopped his sweati
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CHANDNI ONCE upon a time there lived an old man in Almora. He was popularly known as Abbu Khan. He lived all alone except for a few goats which he always kept as pets. He gave his goats f
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CHANDNI Are these goats mad, he wondered! Or was it their love for freedom! But freedom meant struggle, hardship, even death. Abbu Khan couldn’t solve the mystery. One day, when all hi
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CHANDNI She had a friendly temperament, and would listen to Abbu Khan’s tales with a lot of interest and affection. Abbu Khan called her Chandni, which means ‘moonlight’.
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CHANDNI Every morning Chandni watched the hilltops bathed in the sunlight. “How beautiful those hills are!” she thought. “How refreshing the breeze that blows through them! And ho
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CHANDNI “Fight the wolf, indeed! Have you forgotten the story of your sister Kalua who was the size of a big deer. She fought the wolf through the night but was killed in the mornin
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CHANDNI Chandni reached the hills. It seemed to her that the old hills were standing in a row to welcome her. She felt like a child meeting her parents after years of separation. Wherever she we
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CHANDNI Should she go back to the safety of Abbu Khan’s hut? “No,” she said to herself, “death in an open field is far better than life in a small hut”. The wolf h
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THE BEAR STORY THERE was once a lady who lived in an old manor-house on the border of a big forest. This lady had a pet bear she was very fond of. It had been found in the forest, half dead of hung
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THE BEAR STORY He had never tasted meat; he ate the same food as the dogs and often out of the same plate—bread, porridge, potato, cabbage, turnip. He had a fine appetite, and h
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THE BEAR STORY He was also put on the chain on Sundays when his mistress went to spend the afternoon with her married sister who lived in a solitary house on the other side of the mountain-lak
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THE BEAR STORY The lady was very angry, she was already late for lunch, there was no time to take him back home, she did not want him to come with her, and, besides, it was very naughty of hi
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THE BEAR STORY When the lady came home in the evening, the bear was sitting in his usual place outside his kennel looking very sorry for himself. The lady was still very angry. She went up to him a
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A TIGER IN HOUSE TIMOTHY, the tiger-cub, was discovered by Grandfather in the Terai jungle near Dehra. One day, when Grandfather was strolling down the forest path at some distance from the rest
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A TIGER IN A HOUSE Timothy was provided with two companions —Toto, the monkey, who was bold enough to pull the young tiger by the tail, and then climb up the curtains if Timothy lost his
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A TIGER IN THE HOUSE Timothy had clean habits, and would scrub his face with his paws exactly like a cat. He slept at night in the cook’s quarters, and was always delighted at being
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A TIGER IN THE HOUSE He licked Grandfather’s hands and only sprang away when a leopard in the next cage snarled at him. Grandfather ‘shooed’ the leopard away, and the tiger re
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A TIGER IN THE HOUSE Grandfather went in search of the Superintendent of the zoo, but found that he had gone home early; and so, after wandering about the zoo for a little while, he returned to Tim
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AN ALIEN HAND BEFORE YOU READ Have you heard of the Viking Mission to Mars? The National Aeronautics and Space Administration’s (NASA) Viking Mission to Mars was composed of two spacecr
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AN ALIEN HAND “TILLOO! How often have you been told not to go that way?” “But why does Daddy go there every day?” “Because that’s his job, Tilloo!”
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AN ALIEN HAND Gently but firmly he was escorted by the security staff back home to an anxious and angry mother. While he was being scolded he received help from an unexpected quarter
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AN ALIEN HAND “Daddy, can I join the team when I grow up?” “Of course, if you want to,” said his father. “But for that you must be a good boy and do as
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AN ALIEN HAND A spacecraft? Where from? The solar system wasn’t known to have any life anywhere else except on their planet. Tilloo’s father recalled the ancient days recorded in the ar
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AN ALIEN HAND If we destroy these spaceships or render them ineffective, we might reveal our existence.” The President looked at Number Three, a social scientist. He rarely agreed with Num
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AN ALIEN HAND “What a funny looking thing, Daddy! What does it contain?” Tilloo asked. His father shook his head, “Can’t say for sure. We are only allowed to observe it f
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AN ALIEN HAND A mechanical hand was emerging from the spacecraft. It was approaching the surface of the planet. It bent and touched the soil. What was it up to? People crowded towards the
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A TALE OF TWO BIRDS THERE once lived a bird and her two new-born babies in a forest. They had a nest in a tall, shady tree and there the mother bird took care of her little ones day and n
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A TALE OF TWO BIRDS Days passed and the baby birds became big birds. One day, the king of the country came to the forest to hunt. He saw a deer and rode after it. It ran deep into the forest follow
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A TALE OF TWO BIRDS “Welcome, Sir,” he said to the king. “Please come inside and make yourself at home. You look tired. Rest for a while. Then you can share my food.” The
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THE FRIENDLY MONGOOSE ONCE a farmer and his wife lived in a village with their small son. They loved him very much. “We must have a pet,” the farmer said to his wife one day.
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THE FRIENDLY MONGOOSE Both the baby and the mongoose grew. In five or six months the mongoose had grown to its full size — a lovely animal with two shining black eyes and a bushy tail. The fa
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THE FRIENDLY MONGOOSE The baby was fast asleep. But on the floor lay a black snake torn and bleeding. In a flash she realised what had happened. She ran out looking for the mongoose. “Oh!
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THE SHEPHERD’S TREASURE IN a village in Iran there once lived a shepherd. He was very poor. He did not have even a small cottage of his own. He had never been to school or
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THE SHEPHERD'S TREASURE As soon as the shepherd saw the traveller coming towards the cave, he rose to welcome him. He took the tired traveller inside the cave, gave him water to drink and a sha
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THE SHEPHERD'S TREASURE After all,they said mockingly, he was an ordinary shepherd and could behave no better. At first the king did not pay attention to these reports, but how long could he
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THE OLD CLOCK SHOP CHRISTMAS Eve had arrived. As last-minute shoppers were going home, a thick, white sheet of snow lay over Salt Lake City, USA. Yet the lights were still burning i
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THE OLD CLOCK SHOP He was not a pawnbroker, but at the same time couldn’t say ‘No’ to the needy people who placed their old watches or clocks before him for anything they could ge
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TANSEN YOU may have heard the name of Tansen — the greatest musician our country has produced. A singer called Mukandan Misra and his wife lived in Behat near Gwalior. Tansen was their onl
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TANSEN A famous singer named Swami Haridas was once travelling through the forest with his disciples. T ired, the group settled down to rest in a shady grove. Ta
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TANSEN Tansen had, by this time, become very famous. Sometimes he sang before Emperor Akbar, who was so impressed by him that he insisted Tansen should join his court. Tansen went to Akbar&rsquo
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TANSEN Then he had an idea. “If someone sings Raga Megh at the same time, and sings it properly, it will bring rain. Perhaps our daughter, Saraswati, and her friend, Rupvati, could do it
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THE MONKEY AND THE CROCODILE ONCE, on the bank of a river, a monkey made a home for himself in a tree laden with fruit. He lived in it happily eating to his heart’s conten
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THE MONKEY AND THE CROCODILE The monkey plucked some from the nearest branch and threw them down. The crocodile found them delicious. “Thanks,” he said. “May I have some
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THE MONKEY AND THE CROCODILE His wife was furious and she dived in to hide herself at the bottom of the river leaving the little ones to pester their father. The crocodile was in a serious dile
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THE MONKEY AND THE CROCODILE The monkey was scared and distressed. But he was sensible and clever like all monkeys. He kept a cool head. Calmly he said, “I’d do anything for y
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THE WONDER CALLED SLEEP WE know enough about what sleep is, though we don’t know what exactly causes sleep. Sleep is a state of rest — an unconscious rest. When we sleep, our body recov
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THE WONDER CALLED SLEEP Several things happen to our body while we are sleeping. As we sink deeper into sleep, our muscles relax more and more. Our heartbeat becomes slower. Our temperatu
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THE WONDER CALLED SLEEP Here is one in which the poet is describing the experience of falling asleep. Read it aloud.
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A PACT WITH THE SUN SAEEDA’S mother had been ailing for a long time — fever, cough, body-ache, painful joints and what not. Treated by a variety of physicians for weeks, she o
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A PACT WITH THE SUN When she became critical, her relatives and neighbours persuaded her to consult a specialist even though his fee was likely to be high. Life is more precious than money, they sa
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A PACT WITH THE SUN Saeeda’s mother was dejected. She muttered, “O Lord of mine, why have you ordered the sun to remain hidden? How will I ever be cured?” Saeeda was playi
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A PACT WITH THE SUN One of them, though, who had made a pact with little Saeeda said, “Sir, I can’t stay back. I’ve given my word to Saeeda whose mother is ill and needs our
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WHAT HAPPENED TO THE REPTILES YOU may not believe this story. But I can tell you it is true, because I have been to Pambupatti, a village on the edge of the jungle. It is on a c
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WHAT HAPPENED TO THE REPTILES Never mind, everyone seemed to be running. Finally, I found myself in Pambupatti, and I saw some villagers gathered near a well. I ran to them, and befo
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WHAT HAPPENED TO THE REPTILES “Oh, Grandfather,” I said anxiously, “don’t say that. What I have seen in my village makes me burn with shame. I never, never want to go back t
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WHAT HAPPENED TO THE REPTILES Everyone came — the pretty excited snakes, the slow thoughtful tortoises, the clever quick lizards, and the moody crocodiles, grumpy because they were out o
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WHAT HAPPENED TO THE REPTILES “No BUTS! Now, listen. I have told the tortoises that they will have to move out of Pambupatti. When they go, we will have more of everything. More foo
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WHAT HAPPENED TO THE REPTILES You never knew when one of them might lose his temper and spit some venom at you! And it took only a little poison to kill you, after all. A few weeks passed an
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WHAT HAPPENED TO THE REPTILES He called a meeting of the crocodiles and said, “Wouldn’t it be wonderful if we, the crocodiles, could have the WHOLE jungle for ourselves? No&n
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WHAT HAPPENED TO THE REPTILES Then one day, a squeaky little voice piped up at one of their meetings, “We know why the forest has gone crazy, don’t we?” Suddenly everyone was s
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A STRANGE WRESTLING MATCH THERE was once a wrestler called Vijay Singh. A tall man with massive shoulders and muscular arms, he towered over others like a giant. Vijay Singh, pe
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A STRANGE WRESTLING MATCH There were murmurs of applause as well as apprehension among the young men. “If you walk alone at night through the Haunted Desert,” one of them said, “y
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A STRANGE WRESTLING MATCH As he walked, the night deepened. The moon was bright and the stars shone clearly in the Rajasthan sky. Still a few miles short of his destination, Vijay Singh remembe
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A STRANGE WRESTLING MATCH They often fainted. But here was this unfeeling creature claiming he wanted to meet a ghost. It didn’t make sense. “Really, I don’t know why
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A Triumph of Surgery I WAS really worried about Tricki this time. I had pulled up my car when I saw him in the street with his mistress and I was shocked at his appearance. He had become hugely fat
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A Triumph of Surgery I tried to sound severe: “Now I really mean this. If you don’t cut his food right down and give him more exercise he is going to be rea
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A Triumph of Surgery The entire staff was roused and maids rushed in and out bringing his day bed, his night bed, favourite cushions, toys and rubber rings, breakfast bowl, lunch bowl, su
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A Triumph of Surgery When they had finished, Tricki took a walk round the shining bowls, licking casually inside one or two of them. Next day, an extra bowl was put out for him and I was please
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A Triumph of Surgery We could hardly believe it when the brandy came to put a final edge on Tricki’s constitution. For a few nights the fine spirit was rolled around, inhaled and re
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The Thief’s Story I WAS still a thief when I met Anil. And though only 15, I was an experienced and fairly successful hand. Anil was watching a wrestling match when I approached him. He wa
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The Thief's Story I thought that over for a minute. Perhaps I had misjudged my man. I asked, “Can you feed me?” “Can you cook?” “I can cook,” I lied ag
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The Thief's Story Anil made money by fits and starts. He would borrow one week, lend the next. He kept worrying about his next cheque, but as soon as it arrived he would go out and celebrate. I
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The Thief's Story When I reached the station I did not stop at the ticket office (I had never bought a ticket in my life) but dashed straight to the platform. The Lucknow Express
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The Thief's Story I went back to the bazaar and sat down in the shelter of the clock tower. The clock showed midnight. I felt for the notes. They were damp from the rain. Anil’s money.
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The Midnight Visitor AUSABLE did not fit any description of a secret agent Fowler had ever read. Following him down the musty corridor of the gloomy French hotel where Ausable had a room,
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The Mid night Visitor Some day soon that paper may well affect the course of history. In that thought is drama, is there not?” As he spoke, Ausa
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The Midnight Visitor Ausable moved to an armchair and sat down heavily. “I’m going to raise the devil with the management this time, and you can bet on it,” he said grim
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The Midnight Visitor Keeping his body twisted so that his gun still covered the fat man and his guest, the man at the window grasped the frame with his free hand to support himself. Then he swu
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A Question of Trust EVERYONE thought that Horace Danby was a good, honest citizen. He was about fifty years old and unmarried, and he lived with a housekeeper who worried over h
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A Question of Trust He had seen the housekeeper hang the key to the kitchen door on a hook outside. He put on a pair of gloves, took the key, and opened the door. He was always careful not to leave
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A Question of Trust It was a quiet, kindly voice, but one with firmness in it. A woman was standing in the doorway, and Sherry was rubbing against her. She was young, quite pretty, and wa
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A Question of Trust Horace said, “I would, of course, cut the telephone wires first and then...,” he hesitated, a smile on his face, “I would make sure that you could do
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A Question of Trust And within an hour Horace had opened the safe, given her the jewels, and gone happily away. For two days he kept his promise to the kind young lady. On the morning of the
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Footprints without Feet THE two boys started in surprise at the fresh muddy imprints of a pair of bare feet. What was a barefooted man doing on the steps of a house, in the middle of London? And wh
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Footprints without Feet He escaped easily enough from the boys who followed his footprints in London. But his adventures were by no means over. He had chosen a bad time of the year to wan
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Footprints without Feet They naturally gave chase. In the end he was able to escape only by quickly taking off his newly- found clothes. So once more he found himself invisible but naked in the chi
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Footprints without Feet Then to his amazement he realised that the room appeared to be empty. He and his wife looked under the desk, and behind the curtains, and even up the chimney. Ther
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Footprints without Feet The scientist was always quick-tempered; now he became furious. “You don’t understand who or what I am!” he shouted. “Very well — I&rsqu
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The Making of a Scientist AT the age of twenty-two, a former ‘scout of the year’ excited the scientific world with a new theory on how cells work. Richard H. Ebright and his c
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The Making of Scientist From the first he had a driving curiosity along with a bright mind. He also had a mother who encouraged his interest in learning. She took him on trips, bought him telescope
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The Making of Scientist At the end of the book, readers were invited to help study butterfly migrations. They were asked to tag butterflies for research by Dr Frederick A. Urquhart of the
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The Making of Scientist Then in the seventh grade he got a hint of what real science is when he entered a county science fair — and lost. “It was really a sad feeling to sit t
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The Making of Scientist In his second year in high school, Richard Ebright began the research that led to his discovery of an unknown insect hormone. lndirectly, it also led to his new theory on th
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The Making of Scientist Ebright and his college room-mate, James R. Wong, worked all that night drawing pictures and constructing plastic models of molecules to show how it could happen.
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The Necklace SHE was one of those pretty, young ladies, born as if through an error of destiny, into a family of clerks. She had no dowry, no hopes, no means of becoming known, loved, and married b
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The Necklace She quickly drew out a printed card on which were inscribed these words The Minister of Public Instruction and Madame George Ramponneau ask the honour
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The Necklace Finally she said, in a hesitating voice, “I cannot tell exactly, but it seems to me that four hundred francs ought to cover it.” He turned a little pale,
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The Necklace She fell upon the neck of her friend, embraced her with passion, then went away with her treasure. The day of the ball arrived. Mme Loisel was a great success. She was the
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The Necklace “Yes, I felt it as we came out.” “But if you had lost it in the street, we should have heard it fall. It must be in the cab.” “Yes, it i
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The Necklace Mme Forestier did not open the jewel-box as Mme Loisel feared she would. What would she think if she should perceive the substitution? What should she say? Would she take her
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The Necklace “Yes, I have had some hard days since I saw you; and some miserable ones — and all because of you ...” “Because of me? How is that?” &ldquo
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The Hack Driver AFTER graduating with honours, I became a junior assistant clerk in a magnificent law firm. I was sent, not to prepare legal briefs, but to serve summons, like a cheap pri
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The Hack Driver “Lutkins? I saw him around here about an hour ago. Hard fellow to catch though — always up to something or other. He’s probably trying to start up a poke
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The Hack Driver He’s not really bad, but it’s hard to make him part with his money. If you try to collect from him, in those fancy clothes, he’ll be suspicious and get away from y
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The Hack Driver “How about something to eat?” I suggested. “Let’s go to a restaurant and I’ll buy you lunch.” “Well, I ought to go h
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The Hack Driver “I know Oliver’s mother. She’s a terror,” Bill sighed. “I took a trunk out there for her once, and she almost took my skin off because I didn’t t
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The Hack Driver That morning my promising legal career almost came to an end before it had begun. The Chief almost murdered me. He hinted that I might do well at digging ditches. I was orde
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Bholi HER name was Sulekha, but since her childhood everyone had been calling her Bholi, the simpleton. She was the fourth daughter of Numberdar Ramlal. When she was ten months old, sh
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Bholi Bholi was seven years old when Mangla was married. The same year a primary school for girls was opened in their village. The Tehsildar sahib came to perform its opening ceremony. He said
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Bholi She did not know what a school was like. She remembered how a few days ago their old cow, Lakshmi, had been turned out of the house and sold. “N-n-n-n NO, no-no-no,” s
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Bholi Bholi did not know what exactly a school was like and what happened there, but she was glad to find so many girls almost of her own age present there. She hoped that one of these girls might
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Bholi “Yes, yes, it will be very easy. You just come to school everyday. Will you come?” Bholi nodded. “No, say it aloud.” “Ye-Y
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Bholi “So what does it matter?” his wife replied. “Forty-five or fifty — it is no great age for a man. We are lucky that he is from another village and does not know about h
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Bholi On Bishamber’s greedy face appeared a triumphant smile. He had gambled and won. “Give me the garland,” he announced. Once again the veil was slipp
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Bholi Ramlal was thunderstruck. The guests began to whisper, “So shameless! So ugly and so shameless!” “Bholi, are you crazy?” shouted Ramlal. “You want to disgrace
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The Book That Saved The Earth &nb
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The Book That Saved The Earth But the strangest thing a book ever did was to save the Earth. You haven’t heard about the Martian invasion of 2040? Tsk, tsk. What do they teach child
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The Book That Saved The Earth NOODLE : It shall be done, sir. (He hands Think-Tank a mirror.) THINK-TANK
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The Book That Saved The Earth NOODLE : (speaking into a microphone) Mars Space Control calling the crew of Probe One. Mars Space Control calling the crew of Probe One.Come in, Captain
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The Book That Saved The Earth THINK-TANK : Elementary, my dear Omega. Hold one of the items up so that I may view it closely. (Omega holds a book on the palm of her hand.) Yes, yes, I
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The Book That Saved The Earth OMEGA : Oh, no, no. But poor Lieutenant Iota has not had her breakf
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The Book That Saved The Earth OMEGA : Listen to them? IOTA AND OOP : (to each other, puzzled
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The Book That Saved The Earth IOTA : There seems to be some sort of code.
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The Book That Saved The Earth THINK-TANK : Excellent. Now, decipher that code. ALL
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The Book That Saved The Earth THINK-TANK : Cease laughter. Desist. This is more and more alarming. The Earthlings have reached a high level of civilisation. Didn’t you hea
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INTRODUCTION In Class IX, you began your exploration of the world of real numbers and encountered irrational numbers. We continue our discussion on real numbers in this chapter. We begin with two v
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Euclid's Division Lemma Consider the following folk puzzle*. A trader was moving along a road selling eggs. An idler who didn’t have much work to do, started to get the trader into a w
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Theorem 1.1(Euclid's Division Lemma) Given positive integers a and b, there exist unique integers q and r satisfying a = bq + r, 0 \(% MathType!MTEF!2!1!+- % feaagKart1ev2aaatCvAUfeBSjuyZ
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EXAMPLES 1 AND 2(Euclid's Division Lemma) Example 1 : Use Euclid’s algorithm to find the HCF of 4052 and 12576. Solution : Step 1 : Since 12576 > 4052, we apply the division lemm
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EXAMPLE 3 AND 4 (Euclid's Division Lemma) Example 3 : Show that any positive odd integer is of the form 4q + 1 or 4q + 3, where q is some integer. Solution : &nbs
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The Fundamental Theorem of Arithmetic In your earlier classes, you have seen that any natural number can be written as a product of its prime factors. For instance, 2 = 2, 4 = 2 × 2, 253 = 11
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Theorem 1.2 (Fundamental Theorem Of Arithmetic) Every composite number can be expressed ( factorised ) as a product of primes, and this factorisation is unique, apart from the order in wh
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Example 5 and 6 (The Fundamental Theorem of Arithmetic) Example 5 : Consider the numbers 4n, where n is a natural number. Check whether there is any value of n for which 4n ends with the digit zero
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Example 7 and 8 (The Fundamental Theorem of Arithmetic) Example 7 : Find the HCF of 96 and 404 by the prime factorisation method. Hence, find their LCM. Solution :
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Explanation of Revisiting Irrational Numbers In Class IX, you were introduced to irrational numbers and many of their properties. You studied about their existence and how the rationals and the irr
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Theorem 1.3 and 1.4 Theorem 1.3 : Let p be a prime number. If p divides a2, then p divides a, where a is a positive integer. *Proof : Let the prime factorisation of a be as f
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Examples 9,10 and 11 Examples 9 :Prove that \(\sqrt2\) is irrational. Solution: Let us assume, to the contrary, that \(\sqrt3\) is rational. That is, we can find integers a
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EXPLANATION In Class IX, you studied that rational numbers have either a terminating decimal expansion or a non-terminating repeating decimal expansion. In this section, we are going to consid
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EXPLANATION In Class IX, you studied that rational numbers have either a terminating decimal expansion or a non-terminating repeating decimal expansion. In this section, we are going to consid
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THEOREM 1.15: Let x be a rational number whose decimal expansion terminates.Then x can be expressed in the form , where p and q are coprime, and the prime factorisation of q is of the f
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Theorem 1.6 Let be a rational number, such that the prime factorisation of q is of the form 2n5m, where n, m are non-negative integers. Then x has adecimal expansion which terminate
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Theorem 1.7 Let x = , where p and q are coprimes, be a rational number,such that the prime factorisation of q is not of the form 2n5m, where n, m are non-negative integers. Then, x has a decimal ex
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Revision of Points In this chapter, you have studied the following points: 1.Euclid’s division lemma : Given positive integers a and b, there exist whole numbers q and r satis
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INTRODUCTION In Class IX, you have studied polynomials in one variable and their degrees. Recall that if p(x) is a polynomial in x, the highest power of x in p(x) is called the degree of
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Explanation You know that a real number k is a zero of the polynomial p(x) if p(k) = 0. But why are the zeroes of a polynomial so important? To answer this, first we will see the geometrical repres
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Case 1 Here, the graph cuts x-axis at two distinct points A and . The x-coordinates of A and are the two zeroes of the quadratic polynomial ax2 + bx + c in this case (see Fig. 2.3).
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Case 2 Here, the graph cuts the x-axis at exactly one point, i.e., at two coincident points. So, the two points A and of Case (i) coincide here to become one point A (see Fig. 2.4).
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Case 3 Here, the graph is either completely above the x-axis or completely below the x-axis. So, it does not cut the x-axis at any point (see Fig. 2.5). So, the quadratic
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Examples Look at the graphs in Fig. 2.9 given below. Each is the graph of y = p(x), where p(x) is a polynomial. For each of the graphs, find the number of zeroes of p(x). SOLUTION:
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EXPLANATION You have already seen that zero of a linear polynomial ax + b is . We will now try to answer the question raised in Section 2.1 regarding the relationship between zeroes and c
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Example 2 and 3 EXAMPLE 2 Find the zeroes of the quadratic polynomial x2 + 7x + 10, and verify the relationship between the zeroes and the coefficients. SOLUTION: We have x2 + 7x + 10
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EXAMPLE 4 and 5 Find a quadratic polynomial, the sum and product of whose zeroes are – 3 and 2, respectively. Solution: Let the quadratic polynomial be ax2 + bx
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EXPLANATION You know that a cubic polynomial has at most three zeroes. However, if you are given only one zero, can you find the other two? For this, let us consider the cubic polynomial x3 –
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Example 6 and 7 EXAMPLE 6 Divide 2x2 + 3x + 1 by x + 2. SOLUTION Note that we stop the division process when either the remainder is zero or its degree is less than the degree of the divis
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Example 8 and 9 Divide 3x2 – x3 – 3x + 5 by x – 1 – x2, and verify the division algorithm. SOLUTION Note that the given polynomials are not in standard form. To carry
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SUMMARY In this chapter, you have studied the following points: 1.Polynomials of degrees 1, 2 and 3 are called linear, quadratic and cubic polynomials respectively. 2.A qu
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Different tastes Jhumpa ran into the kitchen and caught hold of her mother saying, “Ma, I am not going to eat this bitter karela (bittergourd). Give me gur (jaggery) and roti.” Ma
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Gopal was waiting for his mausi’s family to visit them. They will be coming the next day for their holidays. He was thinking about all the fun and nice food that he would have with his cous
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NAAG GUMPHAN Designs of this kind are used in rangoli, embroidery and as wall decoration in Saurashtra, Gujarat and South India. I am Aryanath I can do something special which I am sure n
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Has this ever happened to you? You were eating in the playground, an eagle flew down and took away your roti. You dropped something sweet on the ground and
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Long Long Ago This is a picture of Ghadsisar. Sar means a lake. King Ghadsi of Jaisalmer got it made 650 years ago with the help of the people. All around the lake there are ghats with steps leadin
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What floats – what sinks? Ayesha was waiting for dinner. Today Ammi was making her favourite food – puri and spicy potatoes. Ayesha watched as her mother rolled o
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2nd February 1984 Mountaineering Camp Nehru Institute of Mountaineering, Uttarkashi We were at the mountaineering camp and were very excited. Twenty of us were teachers from Ke
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Blood test Rajat is back at school today. He had been absent for many days. “How are you now ?” asked Aarti. “I’m alright,” Rajat replied softy.
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Reached Golconda At last we reached Golconda. We were glad that didi was with us. Didi studies history and we enjoy visiting different places with her. Shailja: My goodness! This fort i
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Straight from the heart What do you think the earth looks like? Make a drawing of the earth in your notebook. On your drawing show where you are. Take a look at your friends’ drawings t
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A bus journey Today, we were going on a school trip to the Adalaj stepwell (baoli ), about eighteen kilometres from Ahmedabad. We began counting the vehicles&nbs
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A traveller’s tale I am Gaurav Jani and this is ‘Loner ’ – my partner – my motorcycle. But, Loner is never lonely. We are together all the time. I and my m
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A bad dream Help! Help! Save me! Aaahhh! Ooooww… There was screaming and shouting everywhere. The ground was&n
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There was a woodcutter. Everyday in the morning he used to go to the forest to cut wood. In the evening he would sell the wood in the city. One day he went deep into the forest. It was a very cold win
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Have you seen such scenes around you? Have you ever thought of people who do this work? What is our responsibility to keep the place clean? Why do you think people need to do this
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Stars in her eyes (Indian Express, 2007) Just 13 years old, Afsana Mansuri has already jumped over the wall. The wall between her jhuggi and the local basketball court.The w
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Jatryabhai was sitting at the door with his daughter Jhimli. They were waiting for Sidya. It was almost night but Sidya had not come home. Two years back Jatrya’s family came to Mumbai from Sind
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I am a small bajra seed. I have stayed in this beautiful wooden box since 1940. I want to tell you my story. This is a long story but not mine alone. It is also the story of my farmer Damjibhai a
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Dhanu’s village Today all the relatives have come to Dhanu’s house to celebrate Dussehra. They have come with their luggage in their bullock- carts. Dhanu&rs
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Daughter of the jungle Look at the picture. Where do you think these children are off to, with little bundles on their sticks? When you find out you too would want to go with them!
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Aaa chhee! Ashima was sitting near the window and reading. It was windy and there was a lot of dust in the air. Suddenly Ashima sneezed loudly—aaa chhee! Ashima’s parents
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Let us meet some children and see how they reach school. Ö Collect some bricks. Lay them on the ground in a line as shown in the picture. Try walking on them. Was it eas
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&nbs
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My name is Anita Khushwaha. I live in Bochaha village. This is in Muzzafarpur district in Bihar. I stay with my parents and two younger brothers. I study in college. Besides studying, I teach young ch
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Are these animals looking funny ? The artist has drawn wrong ears on the heads of the animals. Give correct ears to the animals in the space given below. Animal E
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Nandu Wakes Up Nandu woke up and opened his eyes. For a few seconds he was not sure where he was. It seemed to him that he was surrounded by a forest of big grey tree trunks. He blinked his eye
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Omana’s Diary 16 May As soon as we had reached the station we checked our names on the reservation chart. Soon the train reached the platform. We saw that the coach was a
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What are these girls doing? They are shouting ‘out’,‘out’,‘out’, it is clear that they are playing a game. What do you call this game? Chedduguddu, H
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In the hills of Uttarakhand there is a place where there are flowers everywhere. This place is called the ‘Valley of Flowers’. In some places, one sees red flowers blooming on bushes, whil
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My name is Chetandas. Many years ago I used to teach children like you. These days I spend my time by writing about the days when I was young. I would love to share some of these with you. A Big Mo
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Look carefully at the picture of the river. Read the words given below. Boat, flowing water, blue, fish, water-plants, river, foul smell, big ship, oil, river banks, factories, washing clothes, an
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17 May It is morning now. Last night I went to sleep early. It was too dark to see anything outside. When the train stop
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17 May Night After our long train journey we reached Kottayam in the night. Valiyamma’s house was not far from the station and we had to take two auto-rickshaws to get there. By then I
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Here are some pictures of families. These are the families of Nimmi, Tsering and Nazli. Let us look at these pictures, talk about what we see and discuss. A New Arrival! There is great excitemen
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What to Drink? Nallamada, Andhra Pradesh Suguna was reading her book, when she heard someone at the door. She saw that there was a visitor from the city. Ap
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I am Basva. My father is a farmer. We live in Belvanika village in Karnataka. It is the month of July. Like every year, Appa, my father, is preparing the field to sow the onion crop. There are so
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Day at night! My name is Vaishali. My father is a vegetable-seller. My whole family – Amma, Bhaiya, Chhotu and I, help him with his work. Can you guess at what time we begin our work? At
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Dear Children, It is 3 o’clock in the afternoon. There are no clouds in the sky. The sun is burning hot. The sparrows, doves and sunbirds have started working in pairs as they prepare to m
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Abdul in the Garden It was a holiday. Abdul was helping his Abbu in the garden. Abbu was clearing the dried leaves and grass from the vegetable beds. Abdul started to pull out the grass from one of
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Class Party The school reopened today after the vacations. The children share news about how they spent their holidays. “When did you put mehendi on
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Trring…! The doorbell rang. When Manpreet opened the door she saw Divya and Swastik there. She called out excitedly, “Gurnoor! Look who has come.
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I came to Mumbai a month ago. Since we came, mother has been admitted in the hospital. We had to come to Mumbai for her treatment The Big City – Mumbai! I have slowly got used to the c
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I came to Mumbai a month ago. Since we came, mother has been admitted in the hospital. We had to come to Mumbai for her treatment The Big City – Mumbai! I have slowly got used to the c
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Tug of War Once again, everybody in Marietta’s family is quarrelling over watching the TV – just like they do every day! Marietta’s brother wants to watch a cricket match whi
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Have you ever seen her photograph anywhere? She is Lieutenant Commander Wahida Prism, doctor in the Indian Navy. She is one of the few women who has worked on a naval ship. She is the first woman
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Chuskit’s Dream Today is a special day for Chuskit. It is so special that last night Chuskit could not even sleep. Do you know why? Chuskit is ten years old, but today she is going to
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Vani and Prasad live in a village called Mukhtapur. Their home is always filled with bundles of bright-coloured threads. Their mother and father and everyone else in
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Today, there was a lot of activity at Maalu’s house. Chittappan and his family were coming home after five years. Five years ago Chittappan had got a job in the
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Let us try making a spicy potato chaat ! Ö For this you need – Ö Boiled potatoes, enough for everybody in the class Ö Salt, red chilly powde
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Ma, please let me go to school today, I have been at home for the past two days. I am getting bored – said Poonam. But you still have fever. Go outside and lie down on the cot – repli
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Last Sunday, we went to a garden in the neighbourhood. We played Hide and Seek (Chhupanchhupai) and Antakshari. We had a lot of fun. After sometime, Didi said – Let us play a new game today. We
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Ch
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After returning home from school, there are two people with whom I like to share all my news. They enjoy listening to my tales. The first person is my nani. She is always anxiou
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We learn so many things when we come to school. But do you know which is our first school? Yes, it is our family. We learn so many things from our family – much before we learn from anywhere els
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Venu's Family Rani's Family Look at the p
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Once there was a sparrow called Phudgudi and a crow called Bhanate. They were fast friends. One day Bhanate said – O Phudgudi! If you lay eggs first then I will eat them and if I lay eggs first
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All the children were playing stappoo (hop-scotch) in the lane. Avantika and her sister Nandita were also playing. But Nandita was not able to play the game in the right way. Avantika: Listen t
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TEAM WORK Let’s sing and dance Teamwork, teamwork, Together we can make our dream work. Then we'll share the joy of what we've do
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MY SHADOW Read and Enjoy I have a little shadow that goes in and out with me. And what can be the use of him is more than I can see. H
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I am a letter. A letter written with a pen and paper by Reena to her friend Ahmed. I was put in a letter box. The postman took me out and put me in a big bag. Taking a ride on the postman’s
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The children in the class were startled on hearing the sound tak. The sound came from the ceiling fan. Kalyani shouted — Look, look a bird is hurt. Peter got up at once and picked up the bird. I
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Madho lives in Bajju — a small village in Rajasthan. It is hardly a village ! All you see is sand all around. One can see some houses when the sand does not blow. Everyone in Madho&rsquo
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CRYING Read and Enjoy Crying only a little bit is no use. You must cry until your pillow is soaked! Then you can jump in the shower and splash-splash-splash! &n
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My name is Naseem. I live in Srinagar. Since yesterday there is lot of activity in our school. It will go on for a week. Do you know why ? There is a camp being held in our school. Children have come
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Chhotu came to Mumbai for the first time… Study the pictures carefully and answer the following : - What did Chhotu th
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Vipul’s f
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Dumb Charades Let us play a game. In this game, everyone has to let others know what they want to tell without speaking. Divide yourselves into groups of seven.
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RIP VAN WINKLE This story is about Rip Van Winkle, a good-natured but lazy man, who goes away falls into the hills and falls asleep. When he awakes twenty years later, Rip finds that quit
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Appu ate bananas Appu likes bananas very much. He plucks and eats bananas from the trees every day.  
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-- Look
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CLASS DISCUSSION 1.What activity was going on in the class? 2.Who was the quiet one in the class? 3.Why was she quiet? (i) she was afraid t
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The Train Come on children, let’s play a game Climb aboard the chugging train! Blow your whistles and take your seats Onto shoulders, if you please! Forward, backward,
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Like other days, Balbir reached the tea stall after his breakfast. His brother Satvinder who had come from the village was also with him. The worker at the tea stall gave him a cup of tea and said
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Tell how many? Come, let us play a game together. You must be familiar with this game. All the children stand in a circle. Let one child stand in the centre and play a tune. Everyone must run in
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Given below is the picture of a hand. Place your hand on it so that the palm faces the paper. Your thumb and fingers should be placed on those drawn in the picture. The hand which fits on the h
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Sajida's sister gave her a very beautiful dupatta. The dupatta had beautiful embroidery and small mirrors stuck on it. After finishing dinner, Sajida tried to wear the dupatta in different ways. S
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By now, you must have read almost the complete book. You have read about trees, water, houses, animals, vehicles and many other things. You must have thought about them as well. Can you tell, why
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TOPSY TURVY LAND Now read about one such upside-down land. The people walk upon their heads, The sea is made of sand, The children go to school
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NOBODY'S FRIEND Read and Enjoy She had some sweets that she wouldn’t share, She had a book that she wouldn’t lend, She wouldn’t let anyone play with
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We see a variety of objects in the world around us. However, we are unable to see anything in a dark
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GENERAL WAYS OF PREVENTING INFECTIONS How can we prevent diseases? There are two ways, one general and one specific to each disease. The general ways of preventing infections mostly relate to preve
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SPECIFIC WAYS OF PREVENTING INFECTIONS What are the specific ways? They relate to a peculiar property of the immune system that usually fights off microbial infections. Let us cite an example to tr
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/ᴂ/ Examples: Cat, Rack, Bat, Exactly, Actually, Had
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/ᴂ/ Examples: Cat, Rack, Bat, Exactly, Actually, Had /e/ Examples: Met, Set, Get, Let, Pen /ɒ/ Examples: Cot, Pot, Shot, Hot, On, Box /ʊ/ Examples: Good, W
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Paheli and Boojho went to a place where a lot of waste material was piled into huge heaps.Something exciting was happening! A crane was moving towards the heap of junk. The long hand of the crane
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There was a general discussion among the children in Paheli and Boojho's class about the places they had visited during the summer vacations. Someone had gone to their native village by a tra
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We see so many objects around us. On the way to school we see things like buses,cars,cycles, trees, animals and sometimes flowers. How do you think, we see objects?Think of the same places a
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/iː/ Examples: She, He, We, Eat, feel, teen, Sheep, Jeep, Cheap /ɜː/ Examples: Her, Were, Girl, Fur, Bird, Third /ɑː/ Examples: Car, Far, Bar, Ask, Calm /ɔː/ Examples:
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/ɪə/ Examples: Beer, near, Hear, Fear, Pier, Here /ʊə/ Examples: Poor, Tour, Hour, Power, Flour /eə/ Examples: Air, Bear, Hair, Fair, There, Where, Liar /eɪ/ Examples: Day, Say, Pay
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We use electricity for many purposes to make our tasks easier.For example, we use electricity to operate pumps that lift water from wells or from ground level to the roof top tank. What are other purp
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Suppose for some reason your family gets only one bucket of water everyday for a week. Imagine what would happen? Would you be able to cook, clean utensils, wash clothes or bathe? What
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We have learnt in Chapter 9 that all living things require air. But, have you ever seen air?You might not have seen air, but, surely you must have felt its presence in so many ways. You notice it
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Objects Around Us We have seen that our food and clothes have so much variety in them. Not just food and clothes, there is such a vast variety of objects everywhere. We see around us, a chair,
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" जिस पुस्तक से यह उद्देश्य सिद्ध नहीं होता, जिससे मनुष्य का अज्ञान, कुसंस्
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We throw out so much rubbishor garbage everyday from our homes, schools, shops and offices. The grains, pulses, biscuits, milk or oil purchased in shops, ar
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'गद्यं कवीनां निकषं वदन्ति ।' गद्य को कवि की कसौटी कहा गया है क्योंकि अच्छ
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'गद्यं कवीनां निकषं वदन्ति ।' गद्य को कवि की कसौटी कहा गया है क्योंकि अच्छ
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दो बैलों की कथा, मेरा छोटा सा निजी पुस्तकालय, मेरा छोटा सा निजी पुस्तकालय
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Orissa was hit by a cyclone with wind speed of 200 km/h on 18 October 1999. The cyclone smashed 45,000 houses making 7,00,000 people homeless. On 29 October the sam
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Soil is one of the most important natural resources.It provides anchorage to the plants and supplies water and nutrients. It is the home for many organisms. Soil is essential for
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All of us use water in our homes and make it dirty. Dirty! Are you surprised? Rich in lather, mixed with oil, black– brown water that goes down the drains from sinks, showers, toilets, lau
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One evening Boojho entered the park with an elderly person. He introduced him to his friends. Prof Ahmad was a scientist working in the university. The children started playing while Prof Ahmad s
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Every day you come across many changes in your surroundings.These changes may involve one or more substances. For example, your mother may ask you to dissolve sugar in water to make a cold drink. Maki
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PHYSICAL CHANGES Activity 6.1 Cut a piece of paper in four square pieces. Cut each square piece further into four square pieces. Lay these pieces on the f
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CHEMICAL CHANGE A change with which you are quite familiar is the rusting of iron. If you leave a piece of iron in the open for some time, it acquires a film of brownish substance. This substance i
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Activity 6.6 (To be demonstrated by the teacher) Get a small piece of a thin strip or ribbon of magnesium. Clean its tip with sandpaper. Bring the tip near a candle flame. It bur
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Activity 6.7 (To be demonstrated by the teacher) Dissolve about a teaspoonful of copper sulphate (blue vitriol or neela thotha) in about half a cup of water in a glass tumbler or a beaker. Add a fe
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Activity 6.7 (To be demonstrated by the teacher) Dissolve about a teaspoonful of copper sulphate (blue vitriol or neela thotha) in about half a cup of water in a glass tumbler or a beaker. Add a fe
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Activity 6.8 Take about a teaspoonful of vinegar in a test tube. Add a pinch of baking soda to it. You would hear a hissing sound and see bubbles of a gas coming out. Pass this gas through freshly
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RUSTING OF IRON Let us get back to rusting. This is one change that affects iron articles and slowly destroys them. Since iron is used in making bridges, ships, cars, truck bodies and many othe
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A change in which one or more new substances are formed is called a chemical change. A chemical change is also called a chemical reaction. Chemical changes are very important in our lives. All new
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CRYSTALLIZATION In Class VI you have learnt that salt can be obtained by the evaporation of sea water. The salt obtained in this manner is not pure and the shape of its crystals cannot be seen clea
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“Jal Hai, To Kal Hai” “If you have water, you can think of the future” You are perhaps aware that 22 March is celebrated as the world
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Activity 16.1 Collect clippings from newspapers and magazines on the news items, articles and pictures related to water shortage. Paste them in your scrapbook and share it with your friends. List s
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HOW MUCH WATER IS AVAILABLE Look at the picture of the earth taken from space. Why does it appear blue? Surely, you can guess! You are aware that about 71% of the earth’s surface
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FORMS OF WATER Are you afraid that continuous use will some day exhaust all the water available for use? You know that water on the earth has been maintained for millions of years by various proces
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Activity 16.3 Fig. 16.5 shows the processes involved in the water cycle. They are labelled by numbers. Match these numbers with the processes given in the jumbled form. Most towns and cities have w
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GROUND WATER AS AN IMPORTANT SOURCE OF WATER If we dig a hole in the ground near a water body we may find that the soil is moist. The moisture in the soil indicates the presence of water
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DEPLETION OF WATER TABLE Water drawn from under the ground gets restored by seepage of rainwater. The water table does not get affected as long as we draw as much water as is replen
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DISTRIBUTION OF WATER The distribution of water over the globe is quite uneven due to a number of factors. Some places have good amount of rain and are water-rich. On the other hand, there
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WATER MANAGEMENT You have read in Class VI that in many places a regular supply of water is Fig. 16.8 Rain map of India 1.Government of India, Copyright 2007 2.Based upon Survey of Ind
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WHAT ROLE YOU CAN PLAY you ever shown concern if you saw a tap leaking in your house, school or any other place? Leaking taps waste a lot of water. You must make efforts to stop this leakage.
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EFFECT OF WATER SCARCITY OF PLANTS You must have seen potted plants wilting and ultimately drying up if they did not get water even for a few days. You have already learnt in Chapter 1 that pl
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You might have seen a beam of sunlight when it enters a room through a narrow opening or a hole.You may have also seen beams of light from the headlamps of scooters, cars and engines of trains [Fig. 1
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headlamps of scooters, cars and engines of trains [Fig. 15.1 (a)]. Similarly, a beam of light can be seen from a torch. Some of (a)Rail engine &n
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LIGHT TRAVELS ALONG A STRAIGHT LINE Boojho recalls an activity he performed in Class VI. In that activity he looke at a lighted candle first through a straight pipe and then through
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REFLECTION OF LIGHT One way to change the direction of light is to let it fall on a shiny surface. For example, a shining stainless steel plate or a shining steel spoon can change
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REFLECTION OF LIGHT One way to change the direction of light is to let it fall on a shiny surface. For example, a shining stainless steel plate or a shining steel spoon can change
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Can you recall the activity in which you got the light of a torch reflected from a mirror? Let us perform a similar activity. Activity 15.1 Take a torch. Cover its glass with a chart paper which
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Activity 15.2 Place a lighted candle in front of a plane mirror. Try to see the flame of the candle in the mirror. It appears as if a similar candle is placed behind the mirror. The candle, whi
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What about the distance of the image from mirror? Let us perform another activity Activity 15.3 Take a chess board. If a chess board is not available, draw on a chart paper 64 (8×8) square
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RIGHT OR LEFT! When you see your image in a plane mirror, is it exactly like you? Have you ever noticed that there is one interesting difference between you and your image in a mirror? Let us find
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RIGHT OR LEFT! When you see your image in a plane mirror, is it exactly like you? Have you ever noticed that there is one interesting difference between you and your image in a mirror? Let us find
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You might have observed that in the side mirror of a scooter or a car the images of all the objects appear smaller than the objects themselves. Have you ever wondered why is it so? PLAYING WITH SPH
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If the reflecting surface of a spherical mirror is concave, it is called a concave mirror. If the reflecting surface is convex, then it is a convex mirror (Fig. 15.12). Why are concave and conv
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We know that the image of an object formed by a plane mirror cannot be obtained on a screen.Let us investigate if it is also true for the image formed by a concave mirror. Take a concave mi
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Boojho observed his image in the shiny surface of the bell on his new bicycle.He found that his image was erect and smaller in size.He wondered if the bell is also a kind of spherical mirror. Can
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IMAGES FORMED BY LENSES You might have seen a magnifying glass. It is used to read very small print (Fig. 15.21). You might have also used it to observe the body parts of a cockroach or an earthwor
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SUNLIGHT — WHITE OR COLOURED? Have you ever seen a rainbow in the sky? You might have noticed that it appears usually after the rain when the Sun is low in the sky. The rainbow is
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In Class VI, you learnt about different types of motions. You learnt that a motion could be along a straight line Can you recall these three types of motions? Table 13.1 Some examples
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In Class VI, you learnt about different types of motions. You learnt that a motion could be along a straight line Can you recall these three types of motions? Table 13.1 Some examples
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SLOW OR FAST We know that some vehicles move faster than others. Even the same vehicle may move faster or slower at different times. Make a list of ten objects moving along a straight path. Group t
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SPEED You are probably familiar with the word speed. In the examples given above, a higher speed seems to indicate that a given distance has been covered in a shorter time, or a larger distance cov
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We can determine the speed of a given object once we can measure the time taken by it to cover a certain distance. In Class VI you learnt how to measure distances. But, how do we measure time? Let us
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The working of clocks is rather complex. But all of them make use of some periodic motion. One of the most well-known periodic motions is that of a simple pendulum. Fig. 13.4 (a) A si
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Units Of Time and Speed The basic unit of time is a second. Its symbol is s. Larger units of time are minutes (min) and hours (h). You already know how these units are related to one anot
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MEASURING SPEED Having learnt how to measure time and distance, you can calculate the speed of an object. Let us find the speed of a ball moving along the ground. Activity 13.3 Draw a st
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DISTANCE TIME GRAPH 13.5 DISTANCE-TIME GRAPH You might have seen that newspapers, magazines, etc., present information in various forms of graphs to make it Table 13.5 Odometer reading at dif
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You might have tried the game ‘How steady is your hand?’ suggested in Chapter 12 of Class VI. If not, you may try it out now. Paheli and Boojho had also set up the game by connecting
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HEATING EFFECT OF ELECTRIC CURRENT Activity 14.2 Take an electric cell, a bulb, a switch and connecting wires. Make an electric circuit as shown in Fig.14.9. This activity has to be done
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MAGNTIC EFFECT OF ELECTRIC CURRENT Activity 14.5 Take the cardboard tray from inside a discarded matchbox. Wrap an electric wire a few times around the cardboard tray. Place a small co
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ELECTROMAGNET Activity 14.6 Take around 75 cm long piece of insulated (plastic or cloth covered or enamelled) flexible wire and an iron nail, say about 6–10 cm long. Wind the wire
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ELECTRIC BELL We are quite familiar with an electric bell. It has an electromagnet in it. Let us see how it works. Fig. 14.20 shows the circuit of an electric bell. It consists of a coil of wire
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SYMBOLS OF ELECTRIC COMPONENT Some common electric components can be represented by symbols. In Table 14.1, some electric components and their symbols are shown. You may come across different symbo
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Deep under the sea See the lovely coloured fish Swimming peacefully This special poem in three lines is called a Haiku .Such poems about nature are popular in Japan. Here is another Haiku-
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2 Shapes and Angles Rohini and Mohini are twin sisters. They love doing the same things. One day when they were making shapes with matchsticks, Shaila gave them a challenge Rohini made this
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FRACTIONS Subhash had learnt about fractions in Classes IV and V
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RATIO AND PROPORTION 12.1 INTRODUCTION In our daily life, many a times we compare tw
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The most wonderful machine in the world is the human body. It is able to perform many functions at any given time. There are different organs in our body that have specific functions. Our nose is u
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Digestive System As soon as we take the first bite of our food, the process of digestion starts. The food gets mixed with the saliva, present in our mouth which is then easily swallowed. From the mou
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Process Of Digestion As soon as we see our favorite food, our mouth starts to water. Saliva The liquid present inside the mouth is known as saliva. It is secreted by the salivary glands. It helps
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Respiratory System Take a deep breath, what do you feel? When you breathe in, your chest gets slightly bigger and when you exhale it comes to the normal size. We breathe in air through our nose
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Circulatory System You must have noticed that when we get hurt, blood starts to come out. Do you know where this blood comes from? It is the heart. The heart, the arteries, the capillaries, and
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Excretory System The excretory system is responsible for removing waste from our body. The kidneys and the bladder help to get rid of the waste product. The waste can be in liquid, solid, or in gas f
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Sense Organs When you touch a hot object, you say ‘Ouch! It’s hot.’ Have you ever wondered how we get to know that it's hot? Whether the object is hot or cold our brain tells u
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Once upon a time, in a small village nestled in the heart of a vast forest, there lived a young girl named Lily. She was a happy and carefree child who loved nothing more than exploring the woods and
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Curious, Lily began to study the symbols, trying to decipher their meaning. As she did so, she began to feel a strange sensation, as if the tree was speaking to her. Suddenly, a beam of light shot out
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For days, Lily explored this magical world, marveling at its wonders and discovering new and exciting things at every turn. She met talking animals, mystical creatures, and even encountered a group of
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Finally, after many long weeks of travel and adventure, Lily arrived at the sorcerer’s castle, ready to face him in a final showdown. With all of her strength and courage, Lily battled the sorce
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Have you ever been to a park, to a riverside or a busy market area? Lots of people come here for fun, for work and for entertainment, and when they go back home, they leave behind a mountain of smelly
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Trash that is left around us attracts germs, flies, mosquitoes and insects. Rotten fruits and decaying food stuffs emit poisonous gases and bad smell which are extremely harmful for our health. But wo
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The sun descending in the west, The evening star does shine “The birds are silent in their nest, And I must seek for mine, “The moon, like a flower, In heaven
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Etiquettes are the appropriate rules of behaviour in a society. These are usually unwritten rules. It is very important to do the right things when you are on the road. Everybody should follow travell
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Stay well away from the edge of the pavement if you are waiting for a van or a bus, or the edge of the station platform if you are going by train. Stay well back until the van, bus or train has stoppe
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Offer your seat to an older person, an adult with a very young child, or someone who is disabled but take care that you hold on to handrails when you stand. Getting Off Be alert and make su
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Tests can really help to know where you are and what you need to do to improve. They let you know if you have understood something that you have been learning and they also help the teacher to plan wh
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Have a tidy study area at home where you haven’t got heaps of stuff around to distract you. Studying with someone can be helpful, but only if you stick to the task. Working alone is best. You wi
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Oh, the wind is blowing through the trees, Whispering secrets with such ease, It dances through the leaves so green, Creating a rustling sound serene. The sun shines bright up in the s
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Introduction to Skeletal System Each day we perform different kinds of activities. We eat, run, study etc. Our bones and muscles work together to do all these various types of activities. We are not
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The Skull The bones of the head make the skull. The skull protects the brain which is located inside our head. It is made up of 22 bones which are joined together. The upper part of the skull has 8
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Limbs In the human body there are two pairs of limbs: Fore limbs (arms) Hind limbs (legs) Fore Limbs (Arms) The bones of the shoulder are attached to our spinal cord with the help of sh
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Joints Joints are a place where two bones meet. Joints help the skeleton to move. All the bones are connected to another bone. The ends of our bones are covered with a thin layer of cartilage which
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There are four types of movable joints: Hinge Joint This type of joint allows movement only in one direction. The elbows, knees, fingers and toes have hinge joints. Ball and Socket Joint T
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Muscles Our bones cannot move on their own, they need something to move them. Muscles are attached to bones and pull to make them move at joints. Every movement needs muscles. There are 640 muscles
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Introduction Classification means sorting out things into groups on the basis of similarities and differences among them. Figure shows three groups of objects. In each group, things are put togethe
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The Five Kingdom System of Classification Now-a-days, scientists classify living things into five main groups called kingdoms. These kingdoms are named as monera, protista, fungi, animalia and
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Bacteria Bacteria are unicellular organisms. They are found everywhere on the Earth. Some bacteria can make their food but others live in and get food from the bodies of other organisms or dead bod
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Classification and Characteristics of Animals Animals are classified into two main groups, i.e. vertebrates and invertebrates. Vertebrates Vertebrates are animals which have a backbone.
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Mammals Human beings, cows, goats, horses, tigers, cats, rabbits, etc., belong to a group of vertebrates called mammals. Mammals have hair or fur on their bodies. Babies of the mammals are fed on t
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Birds Sparrows, crows, parrots, doves, robins, hens and pigeons, etc., belong to the group of vertebrates called birds. Birds have feathers, wings and beaks. They have hollow bones and air sacs, wh
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Reptiles Lizards, snakes, tortoises, crocodiles, alligators, etc., belong to a group of vertebrates called reptiles. Reptiles have dry, thick and scaly skin which covers and protects their bodies.
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Amphibians Toad, frog, salamander, etc., belong to a group of vertebrates called amphibians. They have four limbs. Amphibians can live in water as well as on land. They breathe through lungs or ski
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Fishes There are over 25,000 different kinds of fishes found all over the world. They live in water. They have streamlined bodies well suited to swim fast in water. Fishes have fins and tail wh
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Invertebrates Animals which do not have backbone are called invertebrates. There are different kinds of invertebrates found on the Earth. Insects, snails, starfish and worms are the examples of inv
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Classification and Characteristics of Plants Plants are mainly classified as flowering plants and non-flowering plants. Flowering Plants The plants that bear flowers are called flowering plan
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There is a young plant in every seed of flowering plants called embryo. Embryo bears one or two seed leaves called cotyledons. Cotyledons often store food which is used by the young embryo. Seeds of g
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Introduction We see living things all around us. Animals and plants are the well-known examples of living things. However, there are some groups of living things that we cannot see with our naked e
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Main Groups of Microorganisms (Virus, Bacteria and Fungi) There are many different kinds of microorganisms. They are classified on the basis of shape, structure, feeding habit, etc. Main groups
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Advantages and Disadvantages of Microorganisms Most of the microorganisms do not cause diseases and are beneficial. Some advantages and disadvantages of microorganisms are mentioned below: Advan
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Disadvantages of microorganisms (i) Diseases Many of the microorganisms’ cause diseases in humans, animals and plants. Some viral diseases are common cold, influenza, measles, chicken pox,
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Infection The attack of disease-causing microorganisms in the body of an animal or plant is called infection. Infectious diseases quickly spread from one individual to another.
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Ways to avoid Infection Here are some simple ways to prevent infections: Dirty hands are the major source of germs. Wash your hands frequently especially before eating and after using toile
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Introduction Things around us make our environment. Living things get food, oxygen, water and other necessities of life from their environment. Environmental pollution is a big challenge to life.
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Kinds of Pollution Air, water and land are the parts of environment. Hence, pollution can be divided into following kinds: 1. Air pollution &
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Effects of Pollution 1. Air pollution causes diseases of throat, skin and eyes. Toxic air pollutants enter the human body with inhaled air and cause breathing difficulties, bronchitis and serious d
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Measures to Reduce Pollution Following steps can be taken to reduce pollution: 1. Factories and industries should be shifted away from the cities; 2. Industrial wastes should be treated and m
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Biodegradable and Non-Biodegradable Materials Waste material or pollutants can be classified as biodegradable and nonbiodegradable. The materials which are naturally decomposed into simpler substan
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Impact of Non-Biodegradable Materials on the Environment Non-biodegradable wastes never decompose and remain as pollutants. Non-biodegradable pesticides and other toxic chemicals may cause diseases
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Introduction to Matter Things all around us are made up of matter. Matter has mass and occupies space. Different substances are made up of different kinds of matter. The food we eat, the water we d
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Arrangement of particles in solids, liquids and gases Every kind of matter is composed of small particles which are in constant random motion. Let us discuss the arrangement of these particles in t
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Effect of Heat on the Arrangement of Particles Properties of matter change with a change in temperature. When heated, the particles gain energy, move faster and move away from each other. That is w
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Boiling If we heat a liquid continuously, the movement of its particles becomes faster and faster. Spaces between particles are increased and attractive forces between them become weaker. Finally,
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Role of Evaporation and Condensation in the Water Cycle Sea, river, lake, canal, pond, etc. are called water bodies. The transfer of water from water bodies to the atmosphere and its return back i
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Application of Evaporation and Condensation Water is always present in the air in the form of water vapours. When there is smoke and dust in the cold climate, these water vapours appear as fog
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Science, Technology, Society and Environment Evaporation produces cooling. This principle is used in the technology of making refrigerators and air conditioners, etc. The compressors in the AC and
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Introduction - The Globe Look at the picture of the earth and observe: It is spherical, like a ball. You can see only one-half of it, you cannot see the other half. Now look at the globe i
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Latitudes Latitudes are horizontal lines. The longest latitude is called the Equator. It is drawn midway between the North Pole and the South Pole. Thus, this line divides the earth into two parts.
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Important Latitudes The Equator is the most important latitude and is marked 0°. It divides the globe into two equal halves. Other important latitudes are the following: Tropics: The latitud
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Latitudes and Heat Zones You know that the sun is the source of heat and light on the earth. Let us do a practical. Light a candle and place it just in front of the globe. What do you see?
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Longitudes Latitudes are horizontal lines but longitudes are vertical lines. These lines touch the North Pole on one end and the South Pole on the other end. So, they all are semi-circles. They are
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The Map Introduction A globe is a model of the earth, while a map is a drawing of the whole or part of the earth. Let us first compare these two: Difference between globe and map:
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Types of Maps You are going to visit a famous lake with your family, but don’t know the way to it. What will you do? Tick the options: Keep asking people for directions. Carry a tourist
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Directions, Distance And Scale, Colours Directions The four cardinal directions are : East, West, North and South. The sun rises in the East, sets in the West, it is in the South at noon, which is
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Signs and Symbols A map can include several landmarks, for which special signs and symbols are used. These landmarks can be rivers, forests, railway lines, roads, cities, towns, dams, temples
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Weather And Climate Weather The atmosphere changes from time to time. It is cooler in the morning and warmer in the afternoon. You can see the change in the atmosphere almost every hour. The at
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Factors Influencing the Climate Following are the factors which influence the climate of a place: 1. Distance from the Equator You have read that the areas around the Equator receive direct s
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3. Distance from the Sea Land heats up and cools down quickly. On the other hand, water takes time to heat and cool. So, the land in coastal areas heats up during the day and cools down at night qu
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4. Direction of Winds The temperature of the wind depends on the temperature of the place it blows from; a wind from a cold place cools the surroundings, while a wind from a hot place warms it up.
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Climatic Zones You have read in this book that there are three heat zones in the world. They are also called the climatic zones, as they determine the climate of the world. 1. Torrid Zone: The v
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Pollution Introduction The environment provides us such conditions that life can exist on our earth. There is available on the earth air and water in just right quantities, and these are optima
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Air Pollution The atmosphere is made up of different types of gases, as oxygen, carbon dioxide, nitrogen and others. We inhale oxygen and exhale carbon dioxide. Trees use carbon dioxide and release
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Water Pollution Water is an important ingredient of the environment. Life cannot be possible without it. We need it for different purposes in our homes, fields and industries. When we use water, we
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Soil Pollution Soil is an important natural resource. We need it to plant our trees and produce crops. We have polluted soil with our activities. It occurs in many ways. Farmers mix chemical fer
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We can deal with Non-biodegradable Waste type of pollution in the following ways. Together these are called a 3-R’s formula : Reuse: Instead of discarding things, there are many items tha
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We must take the following steps immediately in our own interest : Plant trees. Make sure no plant dies for want of water. Save water. Never waste water. Dig a pit and put all biodegradable
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Natural Disasters Introduction Disasters can strike anywhere and anytime, and it’s crucial to stay safe during their occurrence. However, it’s equally important to extend help to the v
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We shall study only natural disasters in this class. Earthquake The occurrence of an earthquake is common in the world. In some areas, they keep occurring off and on, like in Indonesia and Japan
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Volcano It is very hot deep inside the earth. Everything is in a molten state there. If there is a deep crack or hole in the earth’s surface, this molten material can flow out at a high s
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Drought Excessive rainfall leads to floods, while a lack of rainfall causes drought. Droughts are often prolonged periods without rain, resulting in water scarcity. This leads to a lack of crops, f
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Disaster Management Owing to large scale destruction, a disaster a is the cause of massive suffering to the people. It can also lead to death of people and animals; diseases can spread and the land
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Coal The steam engine, which ran on coal or wood, was the first effective use of energy. However, it produced a lot of smoke and pollution, and required constant manpower to feed the engine with fu
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Mineral oil and Natural gas Petroleum was first discovered in America in 1857. Gottlieb Daimler saw it burn brightly, and he thought that it could be used as a fuel. He invented an engine in 1885 w
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Electricity Once about 300 years ago, a toy popular among children in the Netherlands was Leyden Jar. It was linked with two wires, one inside the glass and the other outside it. When the two w
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Clean Sources of Energy Electricity is produced from different sources, like coal or water. We can classify sources of energy into two types conventional sources and non-conventional sources. 1.
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The land of ice - Greenland Introduction Of the three climatic zones, the Frigid Zone is the coldest on the earth because of the sunlight being very slanting. This zone is located within the two c
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Greenland Location Greenland is an autonomous province of Denmark and is the third largest territory in North America. It is situated near the North Pole, only about 650 km away. Its total area
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Climate And Natural Vegetation Climate Greenland has very low temperatures throughout the year, with an average temperature below freezing point. Winter temperatures can drop as low as -47°C.
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Wildlife Despite lack of natural vegetation, Greenland is gifted with some unique wildlife. Many fur-bearing animals are found here which can withstand extreme cold. The important species of wildli
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Lifestyle Greenland has a population of around 76.19K, and the original inhabitants are the Eskimos, also known as Inuit. They have adapted to the harsh climate and live in the northwest part of th
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Occupations and Industries Fishing is the main occupation of Greenlanders. Fish processing is a major source of employment; almost every third Greenlander is employed in it. People catch fish for e
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Development Science and technology have helped to improve the quality of life in Greenland. They now have access to electricity supply. Schools, hospitals and clubs can be seen around. Compulsory e
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The Arab Desert Introduction to deserts Deserts are areas with very little rainfall, receiving less than 25 cm per year. Vegetation is sparse in deserts due to the dry conditions. Deserts can be h
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Location Saudi Arabia, situated in the Arabian Peninsula, is mostly a desert land covering almost 80% of the region. The country is surrounded by the Red Sea on the west and the Persian Gulf on the
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Climate Owing to scanty rainfall, which is less than 10 cm yearly, the climate in Saudi Arabia is hot and dry. The Asir region is the only exception with an average annual rainfall of about 30-51 c
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Wildlife Wildlife in Saudi Arabia is limited due to its harsh climate. It includes reptiles, birds, mammals, insects, and spiders. During winter, wolves, foxes, deer, and hyenas can be seen. Howeve
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Trade, Industry and Natural Resources Oil is the most important natural resource. There are a number of huge oil fields in its eastern part and the Persian Gulf. Dhahran, Abquaib and Ghawar are the
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Transport and Communication In spite of the harsh climatic conditions, Saudi Arabia has developed a good network of roads. Now effort is being made to connect villages with good quality roads. Rail
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Prairies: The Land of Grass Introduction Moderately rainy areas are fertile and are suitable for grasslands. However, due to the limited growth of grasses in these areas, they have been converted
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The Prairies Location In the continent of North America, grasslands found in America, Canada and Mexico are called prairies. The word ‘prairie’ is a French word which means ‘me
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Vegetation The prairies are classified into three regions - tallgrass, mixed, and shortgrass. The tallgrass prairie has a moderate climate that supports tall grasses covering hundreds of kilometers
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Lifestyle The original inhabitants of the prairies were Red Indians who led a nomadic life with their cattle. With time, a large number of Europeans have settled here. They have turned the vast pra
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Developing Intelligence Introduction Man is lucky to have been endowed with exceptional gifts from nature, namely the ability to use his brain and hands. Along with his capacity to speak and remem
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The Evolution of Writing Writing is akin to a record, where numerous writers come together to create a wealth of knowledge. This art has proven to be an excellent tool for accumulating knowledge. I
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The Numbers’ Tale Numbers are very important in your life. You need them when you want to divide the candies with your friend, or when you want to compare your marks with those of your friend
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The Story of Paper In the beginning, Early Man recorded his signs and symbols on the ground, tree stems or cave walls. But when he travelled, he could not carry them with him. He did not know ho
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The Art of Printing Before the invention of paper, people wrote on tree leaves, tree bark, and animal skins. Writing on these uneven surfaces was challenging, and binding the leaflets together was
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Script for the blind The books came into being, but unfortunately, the blind could not enjoy this advancement. Louis Braille, a blind French boy, wanted to read books. He thought how he could read.
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There stood a bronze statue of a Happy a Prince in the heart of the city. The figure was inlaid with gold. The eyes were made of sapphires. A large ruby was studded in the sword. One nig
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Next night the Happy Prince told the swallow about the noble writer who was weak and hungry. He said to the swallow, “It is very cold. The poor writer has no fire. He is trying to finish a book
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The Happy Prince told the swallow to give the sapphire of his other eye to a poor girl, who was crying in the nearby lane. The Happy Prince requested the swallow to give outer layers gold, little by l
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There was a time when the animals talked like people. Once near a farm, a rooster sat on a branch of a tall tree. The morning sun was bright, the air was warm and the countryside was quiet. The r
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But what if the hungry wolf comes along? Or the lion? They might eat me up.’ I want to tell you something really great; said the fox. The rooster looked down. ‘What’s it?’
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Springtime magic is in the air, As flowers bloom without a care, The sun shines bright, the birds sing clear, And all around, the world appears. The grass is green, the sky is blue,
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Nature all over the world changes its colours several times in a year. Each of these changes manifests itself in the form of one season. There are four seasons in a year: spring, summer, autumn and wi
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At times, heavy rains cause floods. Autumn comes between summer and winter. Generally, its period is from September to October. During this season, it is neither too hot nor too cold. It is a per
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The modern age is the age of science and technology. In every walk of life, we depend on science. Science has given us a lot of comforts. Science has shortened the distances and has lengthened th
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Philo Taylor Farnsworth did not allow television viewing in his home. He said there was nothing good on it. Computer Over the past few years, computers have become a vastly popular household i
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Philo Taylor Farnsworth did not allow television viewing in his home. He said there was nothing good on it. Computer Over the past few years, computers have become a vastly popular household i
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Work on computers continued in the 20th century: Konrad Zuse’s Z3 was the first programmable computer, invented in 1941. The Colossus computer was the first completely electronic compu
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When I close my eyes and think of home, A picture forms in my mind, all on its own. I see the place where I was born, The house that kept me safe, from dusk to dawn. The porch where I
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Forces and Machines We use force when we do work. We use force when we write on a paper, open a door, pedal a bicycle or push an iron nail into the wood. We cannot see a force but we can see its effe
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Advantages And Disadvantages Of Friction Advantages of Friction Many of our daily life activities such as walking, writing and stopping the fast moving vehicles by applying brakes are due to fri
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Methods to Reduce Friction Friction can be reduced by the following methods Polishing of surfaces Polishing of surfaces of the objects reduces the friction. Using lubricants Use of lubr
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Gravitational Force We know that when a ball is thrown upward it comes back to the Earth. It is easy to go down Stairs as compared to moving upstairs. A cricket ball thrown upward, comes downw
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Lever A lever is a simple machine which turns about a fixed point. When a force is applied at one end of the lever, it turns about the fixed point to lift the load at the other end. The fixed p
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Second kind of lever In the second kind of lever, the load is between the fulcrum and the effort. Bottle opener, wheelbarrow, nut cracker, paper cutter and door, etc., are the examples of
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Light is a form of energy. The Sun is the biggest source of light. Light bulbs, flames of fire, candles, etc., are also the sources of light. Light travels in a straight line. It can travel through di
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Transparent, Opaque and Translucent Objects Objects can be classified as transparent, opaque and translucent. The objects through which light can pass are called transparent objects. Glass, water a
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Light Travels in a Straight Line We can prove that light travels in a straight line. Let us perform an experiment as follows: Experiment Take three similar cardboards and make holes in them at
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Shadow Formation Light travels in a straight line. When an opaque object is placed in the path of the light, it cannot pass through the object. Hence, shadow is formed behind the opaque object. Sha
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Eclipse The Earth moves around the Sun and the Moon moves around the Earth. When the Moon, the Earth and the Sun come in a straight line, an eclipse takes place (Figure a, b). Solar Eclipse
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Introduction All the material objects are composed of extremely small particles called atoms. An atom consists of further smaller particles called electrons, protons, neutrons, etc. Protons
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Electrical Circuit and its Components The path along which electric current flows is called an electrical circuit. Figure shows the flow of electric current from one end of the cell to the other en
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Fuse and its Uses Fuse is a safety device connected in electrical circuits. It is a thin metal wire which allows a specific amount of current to flow through it. If the current exceeds the limit, t
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Static Electricity We have learnt about two types of charges, i.e., positive charge and negative charge. Positive charge appears on an object when it loses electrons. Negative charge appears o
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How do static charges build up? Rubbing of certain materials with one another creates imbalance of positive and negative charges on them. For example, when a plastic comb is rubbed through dry
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Lightning Lightning is an example of static discharge. The patches of clouds during their movement rub against each other. As a result, huge amount of static charges appear on the cloud p
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Electromagnets There is a close relationship between electric current and magnetism. Let us perform an activity to understand the relationship between electric current and magnetism. • Take
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Uses of Electromagnets Electromagnets attract the objects made of iron, nickel and cobalt. They are used widely in our daily life. For example, they are used in magnetic locks, circuit breaker
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Safety and First aid Introduction In previous classes, we have studied that we must follow safety rules everywhere. However, accidents still take place. They cause pain and sufferings. Some of the c
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First Aid Sometimes accidents happen despite following safety measures. A person may get injured and need immediate help. The immediate help given to an injured person, before a doctor arrives
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Fracture: A crack in a bone is called a fracture. A slip or a fall may cause fracture. In case of a fracture, do not move the injured part. Use a splint to provide support. A splint is made of wood
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Object in the Eye: Wash your hand before touching the eye. Wash your eyes with water repeatedly. Do not put any sharp object in the eye to remove the particle. Animal Bites: Animal bites caus
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The Nervous System The nervous system is the most complex of all the body systems. It is also the most important system as it controls all the other body systems and the sense organs. The nervous sys
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Spinal cord: The spinal cord originates from the medulla and extends almost till the lower end of our backbone. It is surrounded and protected by the vertebral column. The spinal cord itself i
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Sense Organs We have five sense organs: eyes, ears, nose, tongue and skin. They are associated with sight, hearing, smell, taste and touch respectively. Our sense organs have special sensory re
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Ears: The ears help us to hear sounds. They help us to maintain balance. They are situated in the head region. The ear is made of three parts— the outer ear though which sound enters; the middl
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Nose: The nose helps us to smell and breathe. There are millions of nerve endings on the upper part of the nose. When the smell reaches these hair like nerves, they send message to the brain thr
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Skin: The tongue helps us to identify different tastes. It also helps us to speak. The surface of the tongue is covered with taste buds. The nerve ending in the taste buds help us to iden
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Food and Health Lucy gets easily tired after playing for a little while. She often suffers from cold and lacks energy which makes her feel weak. However, her friend Sarah plays for hours, doesn&
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Carbohydrates: Carbohydrates are energy giving food. They are also known as starch food. They provide our body with heat and energy; they form a major part of our diet. Rice, wheat, potato, and sug
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Proteins: Proteins are known as the body building food of our body. They are needed for growth and repair of our body. They also help in building muscles. Children need more protein in their diet a
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Water: Almost two thirds of our body is made up of water. Water helps in regulating the temperature of our body and helps in the proper functioning of our organs. We lose water while breathing
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Balanced Diet Food that contains the right amount of nutrients, water and roughage in a meal according to age and lifestyle is called a balanced diet. To stay healthy it is important to have a bala
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Deficiency Diseases A disease is a condition in which a body or any part of the body is not able to function properly. Deficiency diseases occur when a person’s diet lacks in required essenti
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Night Blindness A person suffering from night blindness finds it difficult to see in dim light. The eyes become dull, triangular patches appear on the white portion of the eyes and the skin becomes
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Scurvy Lack of Vitamin C causes scurvy. Scurvy causes bleeding and swelling of gums. The gums get easily infected. Oranges, lemon, amla, tomatoes, and sprouted grains are rich in vitamin C.
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Anaemia Lack of iron in food causes anaemia. It decreases the level of haemoglobin in our body. Haemoglobin is a substance present in blood that carries oxygen. An anaemic person gets tired easily,
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Healthy eating Habit Besides eating a well-balanced diet, we should also take care while cooking food. The food should not be overcooked as it loses it nutrition value. Wash the vegetables be
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One afternoon, a woodcutter was returning home through the forest. He was tired, but proud that he had completed a full day’s work. He saw something shiny behind a big tree stump. It was
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I always dream of flying. I am a brave child by nature. I always imagined to achieve my success in the skies. I live in a mountainous area which is an ideal tourist spot. Flying was my passion. Once I
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There were two men holding the seat of the balloon for the pilot. Robert lit the burners to heat the air and the balloon swelled up. Hot air began to fill the balloon. The pilot sat in his seat. The b
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Thousands of years ago, some fishermen camped for the night on a sandy beach. After they went to sleep, the hot coals from their campfire glowed far into the night. In the morning one of the men n
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Legends say that this may be the way that people first discovered glass. Glass is formed when sand is mixed with certain chemicals in a very hot fire. Perhaps by accident, all of these materials were
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Over the years glass making improved a great deal. Today glass is so clear like crystal that you can hardly tell it is there. Houses can have many large windows. Some city skyscrapers look as though t
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Of all the objects made of glass, lenses are probably the most important. A lens is a specially curved piece of glass that bends light rays. Lenses make things look either bigger or smaller than they
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“Jan,” called his teacher, “don’t forget to tell your father about the hockey match on Friday night.” Jan’s expressions changed. “Why should my father come?&r
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“I know, Jan”, Mr. Wasif said, “but I am sure he wants to know about our national sport as much as you do. Fathers should also have fun in our game. See you both on Friday. By the wa
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They stopped thinking of him as a strange boy. But now Mr. Wasif was asking him to bring his father to school.”Hi, Jan,” called Samy, a dark-haired boy in a red-striped shirt. “I kno
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Jan’s eyes filled with tears, “I know I was wrong, Sir! I am going home now to ask my father to come.” “You don’t need to, Jan. I invited your father myself, and he wants
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Salim shook his fountain pen twice, but it didn’t work. “My teacher is going to punish me. She will not be ready to accept any excuse if I don’t submit my homework assignment,&rd
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As if by magic, clear blue words began to show. Salim moved the paper away from the heat of the bulb. Slowly the words began to disappear. “This is super!” he cried. “Just what I
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Salim collected his books, packed his sneakers for gym the next day, and was ready to put his homework and notebooks in his bag. He looked around, puzzled. He had put his homework on the desk with his
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This time Salim put the homework securely into his notebook. And just to make sure he would find it quickly the next day, he put a paper clip on the top of the page. That morning when Miss Nadia said,
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Sense Of Large Numbers Seven-digit number: This is any number with 7 digits. An example is 89,72,543. In words, it is read as Eighty-nine lakh seventy-two thousand five hundred forty-three.
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Writing Numbers Using Commas While writing a number, different periods are separated by putting a comma between two consecutive periods. Example : Write 40932045 and 375318277 in Indian place value
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International place value International place value chart International place value chart for 9-digit numbers is divided into four periods i.e., ones, thousands and millions which are furt
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Face Value & Place Value The face value of a digit is the value of the digit itself at whatever place it may be. For example: In number 32876521, the face value of 1 is 1, 2 is 2, 5 i
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Numbers on Abacus Representing numbers on abacus:
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Comparing and Ordering Numbers Comparison of numbers refers to the process of determining which of two or more numbers is greater or smaller than the others. Ordering numbers means arranging a grou
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Introduction to Roman Numbers Roman numerals are a system of numerical notation used in ancient Rome and still in limited use today. In this system, different letters represent different values, an
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Roman Number Rules 1. Roman numerals are written using only seven letters: I, V, X, L, C, D, and M. Each letter represents a specific value: I represents the number 1 V represents the number 5 X re
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Writing Roman Numerals Example 1 : Write the following numbers in roman numerals: (a) 1287 (b) 699 (c) 789 (a) 1287 1287 = 1000 + 200 + 80 + 7 = MCCLXX
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Addition Addition is a way of combining things and counting them together as one large group. The numbers that we add are called addends and the result of addition is called sum. Let us learn to ad
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Subtraction Subtraction is a process of taking away. The number from which we subtract is always the bigger number. It is called minuend, The number that is subtracted is called subtrahend and the
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Multiplication Multiplication is a process of repeated addition of the same number. The number that is multiplied is called multiplicand. The number which multiplies is called multiplier and the an
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Division Divide is a process of taking away. The number from which we subtract is always the bigger number. It is called minuend, The number that is subtracted is called subtrahend and the answer i
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Order of Operations to Solve Expression We have already studied four basic fundamental operations ie., addition, subtraction, multiplication and division. Sometimes, we face many problems to simpli
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Use of Brackets If some expressions are enclosed within a pair of brackets, it means that they have to be simplified first before the other operations. To simplify such expressions involving bracke
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HCF HCF is the acronym of Highest Common Factor. It is calculated for two or more numbers. Highest Common Factor (HCF) of two or more numbers is the greatest number that divides the given numbers e
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LCM LCM is the acronym of Least Common Multiple. It is calculated for two or more numbers. Least Common Multiple (LCM) of two or more numbers is the smallest number among the common multiples. T
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Solve real life problems involving HCF and LCM Example 1 (HCF) Find the maximum length of a measuring tape that can exactly measure 18, 24 and 30 metre of wires? Solution We have to find H
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Solve real life problems involving HCF and LCM Example 1 (HCF) Find the maximum length of a measuring tape that can exactly measure 18, 24 and 30 metre of wires? Solution We have
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Solve real life problems involving HCF and LCM Example 1 (HCF) Find the maximum length of a measuring tape that can exactly measure 18, 24 and 30 metre of wires? Solution We have
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Solve real life problems involving HCF and LCM Example 1 (HCF) Find the maximum length of a measuring tape that can exactly measure 18, 24 and 30 metre of wires? Solution We have
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Solve real life problems involving HCF and LCM Example 1 (HCF) Find the maximum length of a measuring tape that can exactly measure 18, 24 and 30 metre of wires? Solution We have
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Understanding Fractions Look at the circle It is divided into 4 equal parts. 1 part out of the 4 is coloured. We say that \(1 \over 4\)of the circle is coloured. \(1 \over 4\)
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Like and unlike fractions Gary’s mother bought two similar cakes. She cut first cake in 8 equal pieces and took 1 piece out She took of the first cak She cut se
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Equivalent fractions Look at the circle. It is divided into 2 equal parts. \(1 \over 2\) of the circle is coloured Now look at this circle. It is d
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Equivalent fractions Look at the circle. It is divided into 2 equal parts. \(1 \over 2\) of the circle is coloured Now look at this circle. It is d
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Equivalent fractions Look at the circle. It is divided into 2 equal parts. \(1 \over 2\) of the circle is coloured Now look at this circle. It is d
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Equivalent fractions Look at the circle. It is divided into 2 equal parts. \(1 \over 2\) of the circle is coloured Now look at this circle. It is d
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Equivalent fractions Look at the circle. It is divided into 2 equal parts. \(1 \over 2\) of the circle is coloured Now look at this circle. It is d
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Addition and Subtraction of Fractions Addition and Subtraction of Like Fractions To add or subtract like fractions, add or subtract the numerators and divide by the common denominator Exa
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Addition and Subtraction of Fractions Addition and Subtraction of Like Fractions To add or subtract like fractions, add or subtract the numerators and divide by the common denominator Exa
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Addition and Subtraction of Fractions Addition and Subtraction of Like Fractions To add or subtract like fractions, add or subtract the numerators and divide by the common denominator Exa
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Addition and Subtraction of Fractions Addition and Subtraction of Like Fractions To add or subtract like fractions, add or subtract the numerators and divide by the common denominator Exa
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Addition and Subtraction of Fractions Addition and Subtraction of Like Fractions To add or subtract like fractions, add or subtract the numerators and divide by the common denominator Exa
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Addition and Subtraction of Fractions Addition and Subtraction of Like Fractions To add or subtract like fractions, add or subtract the numerators and divide by the common denominator Exa
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Multiplication of Fractions Multiplication of a Fraction by a Whole Number Multiplication of a Fraction by Another Fraction To multiply a fraction by a whole number, multiply the numerator of the g
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Reciprocal of a Number Two numbers are reciprocal (multiplicative inverse) of each other, if their product is 1. For Example: \({2\over 5}\times{5\over 2}=1\) \(2\over 5\) and
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Division of Fractions Division of a Fraction by a Whole Number To divide a fraction by a whole number, multiply the fraction by the reciprocal of the whole number. Fraction ÷ Whole num
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Decimals A decimal is a number that is written using the base-ten place value system. A decimal point separates the ones and tenths digits Add and subtract decimals Addition of decimals Yo
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Recognize like and unlike decimals Consider the following decimals: I) 33.2 It has one decimal place ii) 124.35 It has two decimal places. iii) 41.237 It has three decimal places. iv)
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Multiplication of decimals by 10, 100 and 1000 (a)Multiplication of decimals by 10 Multiplying a decimal by 10 is equivalent to forming a new number by moving the decimal point of the given deci
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Division of decimals by 10, 100 and 1000 (a)Division of decimals by 10 Dividing a decimal by 10 is equivalent to forming a new number by moving the decimal point of the given decimal to the left
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Division of a decimal with a whole number Consider the following examples: Example 1 Divide 782.25 by 21 Solution 782.25 ÷ 21 Divide as you would with whole numbers.
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Multiplication of Decimal Numbers Multiplication of a decimal with tenth, and hundredths only Consider the following example Example 1 Find the product of 7.5 and 0.6 Solution :7.5 ×
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Division of Decimal by Decimal (by converting decimals to fractions) Example 1 Divide 0.8 by 0.4 Solution 0.8 ÷ 0.4 \(\frac{8}{10}\div \frac{4}{10}=\frac{8}{10}\times \f
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Use of division to change fractions into decimals Example 1 Convert \(1 \over 4\) to decimal. Thus \(1 \over 4\)=0.25 Remember: Dividend 1 is smaller than divisor 4. W
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Simplify decimal expressions involving brackets (applying one or more basic operations) Example 1 Simplify: 2.1 + (1.3 × 2.1 ÷ 0.7) Soluti
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Round off decimals upto specified number of decimal places Definition: To round a number means to approximate the number to a given value. When rounding look at the digit to the right of the giv
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Convert fractions to decimals and vice versa We have learnt how to convert fraction to decimals in article 4.1.1. We know that: \({1 \over 4}=0.25\)
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Solve real life problems involving decimal Example 1 Noureen bought 6 note books at the rate of Rs. 22.75 per notebook. How much did she pay? Solution Cost of one notebook = Rs. 22.75
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Numbers of 5, 6, and 7 digits Numbers of 5, 6, and 7 digits refer to numbers with a specific number of digits. A number of 5 digits has exactly 5 digits, and can range from 10,000 to 99,99
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Indian place value chart Let us read numbers using an Indian place value chart. Reading 5-digit numbers Example: Let’s read the number 87987 87987 = 80000 + 7000 + 900 + 80 +
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Face value & Place value Face Value The face value of a digit is the value of the digit itself at whatever place it may be For example: In number 36521, the face value of 1 is 1, 2 is 2,
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Number line Jack and Sara are holding a banner to show a number line. The number line shows numbers from left to right in order from smallest to greatest with equal spaces. You c
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Comparing and Ordering Numbers Comparison of numbers refers to the process of determining which of two or more numbers is greater or smaller than the others. Rule 1 : A number with more digits i
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Roman Numbers Roman numerals are a system of numerical notation used in ancient Rome and still in limited use today. In this system, different letters represent different values, and the numbers ar
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Roman Number Rules 1. The Roman numerals are formed by combining different symbols together. The value of a Roman numeral is the sum of the values of its individual symbols. 2. A smaller
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Writing Roman Numerals Example 1 : Write the following numbers in roman numerals: (a) 245 (b) 313
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Writing Roman Numerals Example 1 : Write the following numbers in roman numerals: (a) 245 (b) 313
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Addition of 5, 6 and 7 digit numbers (without regrouping) Addition without regrouping : Arrange the numbers in different groups like ones, tens, hundreds, thousands, ten thousands, lakhs and ten la
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Addition of 5, 6 and 7 digit numbers (with regrouping) Addition with regrouping : Group the numbers into columns like ones, tens, hundreds, thousands, ten thousands, lakhs and ten lakhs. Add the nu
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Properties of Addition Property 1 : Commutative : The answer will be the same even if you change the order of addition. Example : Solve : 34,142 + 58,776 and 58,776 + 34,142 So, 34,142 +
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Mental addition Example 1 : Let’s find the sum of 28 and 44 Step 1: Add 20 + 40 hold, 8 and 4 in mind, 2 + 4 = 6 means 20 + 40 = 60. Step 2: Add 8 + 4 = 12. Step 3: Add 60 +
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Subtraction of 5, 6 and 7 digit numbers (without regrouping) In the previous class, we have learnt the subtraction of two numbers up to four digits. In this class, we will learn how to subtract 5,
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Subtraction of 5, 6 and 7 digit numbers (with regrouping) Subtraction without regrouping : First, separate the numbers being subtracted into columns based on their place value (ones, tens, hundreds
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Mental Subtraction Let’s find the difference between 44 and 28 Count on from 28 to 30. Hold the 2 in your head. 30 to 44 is 10 + 4 = 14. Add the 2 in 14.14 + 2 = 16 is the answer. Fi
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Multiplication In the previous class, we have learnt multiplication up to 4-digit numbers by 1-digit and 2-digit numbers. In this class, we will learn more about multiplication. Multiplication b
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Multiplication problems in daily life 1.The capacity of a drum is 60 liters of milk. How much milk can be collected in 7 drums of such capacity? Answer: 7 Drums can hold 420 litres 2.The
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Properties of Multiplication Property 1: Commutative : The product of two numbers does not change if the order of the numbers is altered, according to this property. For example: 500 &time
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Division Division by 1 digit number Division is a process of repeated subtraction, let’s divide 5 digit number by 1 digit. Example 1: Divide 91756 ÷ 8 Step 1: Divide 9 by
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Properties of Division Property 1: When you divide any number by 1, the result is the number itself and there is no remainder. Example: 9489 ÷ 1 = 9489; 80924 ÷ 1 = 80924; 324994 &
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Word problems A train runs 5,580 km in 36 hours. Find the speed of the train in km/hour. Number of km = 5580 km Time = 36 hours So lets divide the number of km by time. The trai
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Divisibility rules A number is completely divisible by another number if remainder is 0. A whole number Is divisible by 2: if the last digit is 0 or divisible by 2 (even). For example, 54, 98
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Prime and composite numbers Prime number is a number that can only be divided exactly by 1 and itself. Think about number 3. It can only be divided by 1 and 3, without leaving a remaind
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Multiples A number that is completely divisible by another number is a multiple of that number Let’s find multiples of 3 using a number line. Start from 0 and count on in 3 equal st
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Factors Let’s arrange 8 balls in equal groups There is more than one way to do this. The number 8 can be divided by 1, 2, 4 and 8 without leaving a remainder. 1, 2, 4 and 8 are c
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Prime Factorization We can express a number as a product of its prime factors. Factor Tree Method Example 1: Find prime factors of 27 Start with the smallest prime number that is a fac
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Common multiples Example 1 : Can you find common multiples of 2 and 3? Let’s write first ten multiples of 2, 2 4 6 8 10 12 14 16 18 20 Let’s write first ten multip
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Finding LCM using prime factorization We can also find LCM using prime factorization method. Example 1: Let’s find LCM of 6 and 8 using prime factorization method. Step
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Common factors and Highest Common Factor (HCF) Example 1: Can you find common factors of 12 and 18? Let’s write factors of 12. 1 2 3 4 6 12 Let’s write factors
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Finding HCF using prime factorization We can also find HCF using prime factorization method. Example 1: Let’s find HCF of 6 and 24 using prime factorization method. Step 1 : Find prim
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Our body has various parts just like a machine (Figure 1.1). These parts are called organs. Organs work together to make our body work Whenever we look into a mirror we see many of our organs (
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Bones Look at the Figure 1.7. It shows the bones which are present in our body. Bones make up the structure of our bodies. We call this structure the skeleton. An adult skeleton is made up of 206 b
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Muscles Muscles perform many functions in the body. Muscles help us in walking, running, lifting things, writing and many other actions (Figure 1.10). Movement of our Body by Muscles Musc
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Heart Sometimes we get hurt and get a cut, blood flows out and we need a bandage to stop the bleeding. The blood in our body is continuously circulating. It is a need of our body. The flow of blood
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Skin It is an important organ of the body which performs many functions such as it covers the body altogether (Figure 1.16). It stops germs and dirt from getting into the body Figure 1.16: S
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Malaria and Dengue Fever Malaria and dengue are the diseases which are spread by mosquitoes. Malaria is caused by micro-organisms called Plasmodium. Plasmodium are transferred to human blood by the
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The Basic Needs Of Living There are many things around us. Some of them are non-living things like table , chair, book, etc. Some are living things like animals and plants. Living things can grow, ea
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Physical Characteristics of Life Movement Movement is a characteristic of life. Nonliving things cannot move on their own Different groups of animals make different types of movements. This
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Life Cycle Life cycle means different stages which a living thing goes through during its life. Life Cycle of Plants A plant passes through various stages during its life time. • The life
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Environment And Its Types Environment When we talk about our environment, we mean every thing around us which can affect our lives. It includes air, water, sunlight, plants and ani
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Adaptation Of Animals Effects of Organisms upon one another Many kinds of organisms live together in an environment. They influence the lives of one another. Sometimes one organism harms the other
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Eating Habits of Animals Living things in an environment need different amounts of food to meet their energy needs. Green plants make their own food. They make more food than they need. Animals can
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Producers, Consumers and Decomposers Producers Plants prepare food for themselves and for all other organisms. That is why they are called producers. Plants produce various types of food
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FOOD CHAIN Organisms also depend upon one another for food. An animal feeds on plants or animals and is itself eaten by some other animal. A third animal consumes the second animal and so on. For
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Introduction To Matter We see different things around us. Trees, flowers and animals are found everywhere in our surrounding. We also see different objects in our homes and schools. There are mou
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Three States of Matter Matter exists in three physical states that are solids, liquids and gases. Solids A lot of things have fixed volume and fixed shape. Such things are called solids. T
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Effect of Heat on Matter ( Solids, Liquids and Gases ) Things change their state on heating or cooling. Solids melt on heating and change into their liquid states. Liquids boil on heating and chang
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Mixing of Materials Most of the things we find in our surroundings are not in their pure form. They are the mixtures of different substances. For example, soil is the mixture of sand, rocks, moistu
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Filtration Filtration is another method of separating the insoluble and suspended components of a mixture. In this method, the mixture is passed through a porous sheet like a filter paper, a cotton
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Filtration Filtration is another method of separating the insoluble and suspended components of a mixture. In this method, the mixture is passed through a porous sheet like a filter paper, a cotton
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What Is Temperature? When your mother is cooking bread for you and you touch the bread, how does it feel? It feels hot. Again when you are eating an ice cream, how do you feel the ice cream? It feels
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Temperature Scales The numbers written on the thermometer show the degree of hotness or coldness of a body. These numbers are called Temperature Scale. Now-a-days, two types of temperature scales a
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Clinical Thermometer A clinical thermometer is used for measuring the temperature of the human body. Its glass tube is marked in centigrade scale from 35 to 42°C and in Fahrenheit scale from 95
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Take the following safety measures while using thermometers: 1. Keep the thermometer upright while measuring the temperature. 2. Mercury is harmful to health, therefore, in case of breaka
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Our Country - India Introduction India is also known by the names Hindustan and Bharat. India is a democratic country. Here, people belonging to different religions- Hindu, Muslim, Sikh and Christ
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Location as per the world and in the globe The location of India is very unique. It is located in the largest continent of the world that is Asia. India is located in the northern hemisph
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Political And Administrative Divisions India is a vast country. For administrative purposes, the country is divided into 29 States and 9 Union Territories. Delhi is the national capital. The state
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Northern Mountains Introduction The northern mountains in the north of India extend from northwest to northeast of India. The Himalayas, the karakoram mountains and the northeastern mountain ran
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The Himalayas consist of three parallel ranges. 1.The Greater Himalayas or Himadri : It is the highest Himalayan range. Kanchenjunga is the highest peak in India. Many glaciers originate f
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Climate: Greater Himalayas are extremely cold. Lesser Himalayas are pleasant during summer. The Shiwaliks get heavy rainfall. Vegetation: The vegetation of Himalayas varies with the altitud
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Advantage of the Himalayas: The Himalayas are scenic At the same time they are useful to us in many ways: • The Himalayas are like natural hames on our other borders •
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Northern Plains Introduction A plain is a large flat area of fertile land. A large part of Northern India makes up the Northern Plains. This region is plain and flat and extends from Punjab in the
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The Ganga River It is drained by the rivers Yamuna, Ganga, Ghaghara, Gandak, Kosi and Teesta from the Himalayas in the north. The river Ganga originates from the Gangotri glacier. The
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Yamuna River Yamuna is the sub-basin of the Ganga river system. It rises in the Yamunotri glacier and flows through the states of Haryana and Uttar Pradesh before joining the Ganga at Prayagraj. Th
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Importance of Northern plains The area is also rich in ground water sources. Its soils have the capacity to grow any crop of the tropical and temperate regions. They are the largest an
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The Indian Desert Introduction The land to the west of the Aravalli Hills, in Rajasthan, is rocky and sandy. This is the Great Indian Desert, also known as the Thar Desert. It stretches from the
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Climate The Thar Desert remains hot and dry throughout the year. There is very little or no rainfall. In summer days are very hot and nights are cool. In winter, days are warm and nights are very c
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Water supply "There is always very little water. Village women walk long distances to fetch water. The state government is trying to provide water for domestic use and irrigation. Water from R
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Cosatal areas and Islands Introduction The Deccan plateau is flanked by coastal plains on the east and the west. Western coastal plains are washed by the Arabian Sea, whereas the eastern coastal p
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Western coastal plain The western coastal plain stretches from the Gulf of Kutch in the north, to Kanyakumari in the south. Different parts of the coast are known by different names. 1. Gulf o
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Western coastal plain The western coastal plain stretches from the Gulf of Kutch in the north, to Kanyakumari in the south. Different parts of the coast are known by different names. 1. Gulf o
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Eastern Coastal Plains The eastern coastal plains lie between the Eastern Ghats and the Bay of Bengal and stretch from West Bengal to Kanyakumari. These plains can be divided into two parts. 1.Nort
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1. Andaman and Nicobar Group of Islands The Andaman and Nicobar group of islands is located in the deep Bay of Bengal about 1353 kilometres from Chennai. This group comprises 350 big and small isla
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Introduction Weather means change in temperature, humidity, air pressure, conditions of winds, clouds and rain of a particular area. The temporary atmospharic condition of a place is known as weath
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Air pressure The air has weight. The air weight at a particular place is known as air pressure of that place. As the altitude increases, the air pressure decreases. The air pressure is measured wi
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Humidity The amount of moisture in the air is called humidity. The level of humidity is high in areas close to the sea and of maximum rainfall. The level of humidity is low in areas which are dry
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Forests and Wildlife of India Introduction Forests We can see around us different types of trees, plants, 3 shrubs, creepers, bushes and grasses. If they grow naturally, they are called natural
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Types of Forests in India India possesses different types of climates and landforms, so a large variety of trees is found here. The important types of forests in India are as follows : 1.Evergr
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Coniferous Forests : Coniferous forests grow on mountains, so they are also called mountain forests. These trees are tall and have pointed needle-shaped leaves. So, snow cannot settle on them. The
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Significance of Forests Forests are very important and useful to us in many ways. They give us many products like timber, fuel, herbs, gum, honey, rubber among other things. They prevent soil erosi
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Conservation of Forests In view of the significance of forests, it is necessary to protect them. At the same time, we need to cut trees for different needs. Forests are cleared for many reasons, su
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Wildlife India possesses a rich variety of wildlife. Wildlife means different species of animals, birds, insects, fishes and reptiles which live in the nature. The place where an animal normally li
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Minerals in India Introduction Minerals are essential for our comfortable living. We use them for different purposes. They are found deep in the earth. These minerals have to be dug out. For this,
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Types of minerals: Many different minerals are found in the earth. They can be grouped into two types: Metallic minerals and Non-metallic minerals. Metallic Minerals Metallic mineral is a met
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Non-Metallic Minerals Important non-metallic minerals include coal, petroleum, sulphur, phosphorus, salt, mica, gypsum, diamond, limestone etc. Uranium and thorium are also included among non-meta
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Conservation of Minerals Minerals take thousands of years to form, so they are called non-renewable resources. They are available in the world in a limited quantity. If we use them thoughtlessly, t
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Human Resources of India Introduction India is the seventh largest country in the world in terms of land and is the world’s second largest country in terms of population. India’s popul
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Human Resource Development To achieve human resource development, the government has initiated a number of steps. These are mainly in the following directions: Health: A healthy person can work
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Crops and Livestock of India Introduction India is called an agricultural country because about 52 percent of working people are directly engaged in agriculture and livestock Crops Owing to
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Classification of Crops We can divide our crops into different classes. Two main categories of crops are food and non-food crops Rice : Rice is an important staple diet for a large number of
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Cash Crops Cash crops are grown for sale in the market, and not for domestic consumption. Important cash crops include sugarcane, cotton, jute, oilseeds, spices, fruits, vegetables and beverages e
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Some crops can also be grouped as follows
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Live Stock Wild animals live in their natural habitat, like the forest. On the other hand, domestic animals are used and reared for different purposes such as food, skin, bone, hair, transportatio
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Industries in India Introduction In past, human desires and necessities were very limited. The basic needs were food, clothes and shelter. With the passage of time, these desires and basic necess
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Goods and Services Goods Goods means such things which we can see, touch and use in our daily life. Example : fruit, dress, car, house and chair etc.
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On the basis of raw material used, industries can be of two types
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On the basis of size, capital and number of workers, industries can be classified into three types:
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Industrial Development in India India is emerging as a large industrial power. We are competing with the most industrialised nations of the world. We are already the sixth largest economic power.
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It was Sunday morning Jack could not wait to go out and play with the boys of his community. Cricket was his favourite sport, and playing it was something he looked forward to all week. After
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Enthusiasm soon turned into horror as Jack saw where the ball landed. It had crashed into the window of the most terrifying man in the neighbourhood - Scary Uncle Jose. Scary Uncle Jose was an old man
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He could not resist his curiosity, so he pointed towards the trophies. Uncle Jose laughed and told him that he had been the Captain of the Indian Cricket Team about forty years ago. He had played agai
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The day Rebbeca had been waiting for had finally arrived. It was her tenth birthday. Rebbeca had spent hours and hours making arrangements for this very special day. She wanted everything to be perfec
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Rebbeca looked at the clock and realized that it was already two o’ clock. Her guests would be arriving any minute now Rebbeca wondered what gifts she would receive. What she wanted the most was
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She even asked the teacher to change her seat so she would not have to sit next to Sara. This was the longest the two girls had ever gone without speaking to each other. On the third day of their figh
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The two girls hugged and Sara explained that her mother caught a bad case of food poisoning on the morning of Rebbeca’s birthday. She said she had tried to explain this situation to Rebbeca many
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When crossing busy traffic streets It can be tricky, let me say. It’s something I am required to do Almost every single day. I’ve learned these little safety
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Lisa wanted to be just like her grandmother when she grew up. Grandma was special because her fingers worked like magic. Within minutes, she could use her silver knitting needles to knit anything Lisa
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One morning, Lisa woke up late for school. She forgot that it was Grandparents Day. Her teacher had asked every student to bring one item from home that described their grandmother or grandfather.
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Did somebody in class steal them? Did she forget them somewhere? Lisa could not help crying. Lisa hesitantly walked into Grandma’s room. “Lisa, I’m so glad you’re home. I can&r
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Early the next morning, the bell rang before it was time for Lisa to catch the bus. When Grandma opened the door, she was surprised to see the bus driver standing there, holding nothing else but her s
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Julia was a kind and compassionate girl who loved helping others. She always tried to use science to solve problems around her. From a young age, she showed potential to be a scientist someday. On
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Julia wanted to attend this program more than anything, but she was scared. She knew her mother would never let her travel to any nearby community, even if it was to teach those in need. She remem
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Just as she was wondering how this could have happened, her father, William, walked into the room. He had just returned home from his shift at the village hospital. He saw the joy on his daughter&
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Comparing numbers Greater than Which box has more Chocolates? The box on the left has more sweets. We can show this as Greater than ‘>’ If one value is large
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Comparison Rules Rule 1: If a number has more digits than another, it is the greater of the two. Example: Compare 3457 and 621. Solution: Here, the number 3457 has 4 digits and the number
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Addition without carrying Addition is to collect them together. Here, we will learn the addition of four-digit numbers. We can add two or more numbers together at a time. The numbers which we add a
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Addition with carrying Example: Find the sum of 1253 and 4936 Solution: Step 1 Write the given numbers in the columns of thousands, hundreds, tens, and ones. Step 2 Add ones, 3 o
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Addition problems in daily life Example: There are 20 apples and 30 mangoes on Benjamin’s cart. How many fruits are there altogether? Solution: There are 50 fruits altogether
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Properties Of Addition Property 1: Numbers can be added in any order, the sum remains the same. Example : Lucas bought 3 red balloons and 2 blue balloons. How many balloons does Lucas have?
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Example Find the sum of 12 and 26. 12 + 26 = ? 12 = 10 + 2 26 = 20 + 6 Step 1 Add tens, 10 + 20 = 30 Step 2 Add ones, 2 + 6 = 8 Step 3 Add both answers,
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Example: Find the difference between 5676 and 3213. Solution: Step 1 Write the given numbers in the columns of thousands, hundreds, tens, and ones Step 2 Subtract ones, 6 ones &ndas
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Example: Subtract 4936 from 9253. Solution: Step 1 Write the given numbers in the columns of thousands, hundreds, tens, and ones. Step 2 Subtract ones, 3 ones - 6 ones is not possible,
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Example: William has 16 goats in his farm. He sold 5 goats. How many goats were left on his farm? Solution: William has 16 goats, He sold 5 goats. Number of goats left: William h
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properties of subtraction Property 1: When 0 is subtracted from a number, the difference is the number itself. For example: 7217 - 0 = 7217 Property 2: When a number is subtracted from itsel
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Review: Multiplication As Repeated addition Look at these examples. There are 2 groups. Each group has 4 bananas There are 3 groups. Each group has 2 apples. Ther
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How many stars are there altogether? There are 4 groups. Each group has 2 stars. 2 + 2 + 2 + 2 = 8 4 × 2 = 8 We read it as four times two equals eight How man
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Multiplication Tables Let’s quickly revise the tables we learned.
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Multiplication of a 4 - Digit Number by a 1 - Digit number Example: Multiply 1424 by 2. Solution: Step 1: Write the given numbers in multiplication form. Step 2: Multiply the ones: 4 ones
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Example: Multiply 1265 by 5. Solution: Step 1: Write the given numbers in multiplication form Step 2: Multiply the ones : 5 ones × 5 ones = 25 ones. Write 5 under ones column and car
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Multiplication By Two Digit Numbers Example: Multiply 65 by 32. Solution: Step 1: Write the given numbers in multiplication form. Step 2: Multiply 65 by 2 ones : 65 × 2 ones = 130 ones
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Properties Of Multiplication Property 1: Numbers can be multiplied in any order. The product remains the same. For example: 4 × 5 = 5 × 4 = 20 Look at the picture.
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Henry has 6 sweets. Lucy has also 6 sweets. How many sweets do they have in total? There are 2 children. Each child has 6 sweets. 2 × 6 = 12 (2 times 6 = 12) Henry and Lucy ha
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Our Solar System The sun and its nine planets, along with their moons, make up a family called the solar system. The Sun is a star. It is only one of millions and millions of stars in
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The Earth: The earth is at the right distance from the sun and has right mixture of air, heat and water which makes life possible on earth. It is the only planet where life is known to exist.
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Life on the earth is possible due to the sun, air and water. Habitat The place where the living things dwell is called their habitat. The sun is the biggest source of light and heat on the Earth
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Wildlife: Animals Living in the Forest Wild animals live in jungles, deserts or in the water, just as human beings live in villages and cities. The areas of the earth where trees and plants grow i
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Living Things Found in Desert Part of the Earth where there is sandy soil, shortage of water and vegetation is called desert. It receives little rainfall. Only such animals and plants which can
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Aquatic life Living Things Found in Water Water is a habitat of many animals and plants. For example, frog, fish, dolphin and fungus live in water. Hippopotamus also lives in water. The anim
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Animals of the Snowy Regions Some parts of the Earth remain covered with snow throughout the year. The plants and animals found in these areas can survive in extreme cold weather. Thick skin an
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Life cycle of a butterfly Eggs : A butterfly first starts out as an egg. A girl butterfly lays small, round eggs on a leaf. She lays the eggs really close together. Caterpillar : A cat
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Life cycle of a frog Egg : Tiny frog eggs are laid in masses in the water by a female frog. The eggs hatch into tadpoles. Life cycle of a frog Tadpole : (also called the polliwog) This stag
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Life cycle of a hen The hen lays eggs. She sits on eggs for 21 days. It is called incubation. After 21 days chickens hatch from eggs.
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Life cycle of plant Growth of plants A seed gradually grows into a plant. 1. Planting Seed is planted, watered, and warmed by the sun. 2. Germination Roots emerge from seed undergroun
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Shadow A shadow is a dark shape formed when an object blocks the passage of light. A shadow is always formed on the opposite side to the source of light. Everyday, the sun rises from the s
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Directions In the morning, if you face the rising sun, it means you are looking towards the East. Your back will be towards the West. Your right hand side is the South while your left hand side is
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We have many things around us. There are also job opportunities for us. We use them to meet the needs of our life. All these things are called resources. The resources are of three types: 1. Natur
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Renewable Resources Resources that can never run out or can replenish through natural processes after a finite interval of time are said to be renewable resources. Eg. forest, wind, water and solar
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Non-Renewable Resources These are finite resources or we can say that they are exhaustible resources, once they are exhausted, it will take them millions of years to form. Eg. Minerals, fossil f
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Human Resources The skills and abilities of a person are called human resources. For example, masons have skills to construct buildings. A painter makes these buildings beautiful by paintin
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Capital Resources A man uses his wealth to make such resources which become a source of income. These resources are called capital resources. For example, bus, car, tractor, computer, fa
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Animals need food for their energy and growth. All animals do not eat similar food. Some animals eat only grass and plants, some eat meat while some animals eat both plants and meat. Herbivores
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Carnivores The animals which eat only meat are called carnivores. Carnivores depend on the meat of other animals. They have long, sharp and pointed teeth. For example, lion, tiger, hyena, wolf etc
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Good heath and Balanced diet Hygienic environment, suitable balanced diet, regular exercise and proper sleep ensure good health What Vegetables should we have? For good health, we use veg
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Occupations Teacher School is where we learn things. Our teachers teach us how to read and write. They teach us to be honest, to tell the truth, to be on time, and to be brave. They teach us how t
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Doctor Our health is taken care of by the doctor. When we get sick, he takes care of us. After a checkup, he gives us medicine. He gives us shots sometimes to protect us from diseases like typhoid,
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Postman The postman is an important person. He goes to the postbox to get the post and then takes it to the post office. Some post carriers pick up letters from the old office and take them to
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police The police keep people safe and help keep the law and order. The police catch thieves and bad people. They keep the crowd from getting out of hand. They help people find children who live in
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Barber In a salon, a barber is the person who cuts our hair. We should take care of our hair if we want to look smart. There are many salons for both men and women in most cities today. A salon tha
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Civil Engineer A civil engineer is someone who builds different kinds of buildings, like homes and places of business. He also builds overpasses. There are a lot of real estate companies wher
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Ancient people-their living Early Days Today after coming from school, Andrew and Angela were waiting for their father as they needed his help in doing their homework. Father came back from his jo
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Invention of wheel and use of metals played a vital role in human civilization. To meet his food requirements, man started cultivation and cattle farming. Beside getting milk and meat from anim
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Percentages Recognise the percentage as a special kind of fraction. Percent: A ratio whose denominator is 100. The symbol for percent is %. The model on right has 25 out of 100 squares
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Convert percentages to fractions, decimals and viceversa (a)Conversion of percentage to fraction and decimal Example 1 Convert 13% to fraction and decimal. Solution 13%
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Finding the percentage of a number To find the percentage of a number, convert the given percentage into a fraction and then multiply it by the given number Example : Find the value of 30% of 60
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Distance Distance is a numerical description of how far apart objects are. Conversion of Units of Lengths We can covert the unit of distance from one unit to another using the given chart.
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Time Time is measured using seconds, minutes, hours, days, weeks, months and years. Clocks measure time in seconds, minutes, hours. Calendars are used to keep the records of days, weeks, months and
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Temperature Temperature is one of the basic physical quantities of science. It’s a numerical representation of how cold or hot an object is. Temperature is defined as the degree of heat prese
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Unitary Method Describe the concept of unitary method Unitary means “of one”. In unitary method the cost of several objects is given and then by finding the cost of one object we can
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Direct and Inverse Proportion Define ratio of two quantities A ratio is a relation between two quantities of the same kind. It can be expressed as a fraction. The symbol for ratio is a colon (:)
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Measurement In the previous class, we have studied that the basic units of measuring length, weight and capacity are metre (m), gram (g) and litre (l) respectively. In this class, we will study more
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Measurement of Weight Gram is the basic unit of measuring weight. The units smaller than the basic unit are named by adding prefixes deci, centi, milli and so on while the units bigger than the bas
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Measurement of Capacity Litre is the basic unit of measuring capacity. The units smaller than the basic unit are named by adding prefixes deci, centi, milli and so on while the units bigger than th
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Fundamental Operations on Measurement Example: Mohan covered a distance of 15 km 275 m in the first hour and 18 km 803 m in the second hour. What distance did he cover in two hours? Solution: Di
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Angles Recall an angle and recognize acute, right, obtuse, straight and reflex angle We have learn’t about an angle and its different types in previous classes. However we recall these con
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Draw Acute and Obtuse angles of different measures using Protractor Draw an Acute Angle Draw an angle of measure 40°. Steps of Construction: (I)Draw a ray QR (II)Place the straight
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Draw an angle equal in measure to a given angle Steps of Construction (I)Measure the given angle ABC with the help of a protractor that is ∠ABC=50°. We have to draw an angle equal
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Draw an angle twice in measure to a given angle. Steps of Construction (i)Measure the given angle ABC with the help of a protractor ∠ABC=40°. We have to draw an angle twice in m
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Draw an angle equal in measure to the sum of two angles Steps of Construction (I)Measure the given angles ABC and LMN with the help of protractor and note that ∠ABC = 40° and ∠LMN =
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Construction of Angels We have to construct a right angle, a straight angle and a reflex angle. We shall construct these angles one by one. Right Angle Construct an angle whose measure
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Straight Angle Straight Angle Construct an angle of measure 180° Steps of Construction: 1.Draw a ray QR 2.Place a protractor on QR such that its central point falls on Q and th
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Reflex Angle Construct an angle of measure 210°. Now, 210° = 180° + 30° Steps of Construction: (i)Draw a ray YZ. (ii)Place a protractor on \(\overrightarrow{YZ}\)
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Triangles Definition of a Triangle A triangle is a simple closed figure having three sides and three angles. (i) In the given triangle ABC: (ii)A, B and C are the vertices. (iii)AB, BC a
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Construction of triangles when three sides are given Equilateral Triangle Example: Draw an equilateral triangle PQR whose measure of each side is 3cm. Solution: Steps of Construction
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Quadrilateral A closed plane figure with four sides is known at as a quadrilateral. It has also four angles and four vertices.
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Recognize the kinds of Quadrilateral Following are the different kinds of quadrilateral. (i) Square (ii) Rectangle
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Construction of Square and Rectangle Square We know that a square has four equal sides and each angle is of 90° . Example Construct a square with length of each side 2.5cm. Sol
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Perimeter and Area Recognition of Region of a Closed Figure Region of a closed figure comprises of the surface enclosed by the boundary and the boundary of the figure itself. The regions of
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Perimeter (i)Perimeter of a square We know that a square has four sides of equal length. To find the perimeter of the square, we add the lengths of four sides of a square i.e; Perimeter o
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Area of a Square and Rectangle (i) Area of a Square The area is the product of length and breadth. In a square length of each side is equal i.e. length = breadth = side A
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Application of formulas to find Perimeter and Area of a Square and a Rectangular Region Example 1: Find the perimeter and area of a square whose side is 12 cm. Solution: Length of the side
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Solution of Appropriate Problems of Perimeter and Area Example 1: The length of a square shaped room is 5 metre. Find the cost of flooring at the rate of Rs.900 per square metre Solution:
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Data Data is a collection of information in the form of numerical figures. It can be arranged and displayed in the form of tables, graphs or charts, In the previous classes, we have learn't to
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Pie Chart Data can also be represented by dividing a circle into sectors, Such representation of data is called a pie chart or circle graph. Pie charts are circular in shapes. Each section of the p
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Review Two Digit Numbers 1 block =1 one Group of ten blocks =1 ten How many tens and ones are in 53? There are 5 tens. They represent 50 blocks. There are 3 ones. They rep
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Three Digit Numbers Ten tens added together equal one hundred. How many hundreds, tens and ones are in 146? There is 1 hundreds, 4 tens and 6 ones in 146. 146 = 1 hundred 4 tens an
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Abacus On Three Digit Numbers Here is shown an abacus with 3 sticks. Each stick has some beads in it. Starting from the left, the numbers of beads show the numbers of hundreds, te
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Four Digit Number Jack has 10 coins of one hundred each. 2 3 4 9 = 2 thousands 3 hundreds 4 tens 9 ones
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Abacus On Four Digit Numbers Here is shown an abacus with 4 sticks. Each stick has some beads in it. Starting from the left, the numbers of beads show the numbers of thousands, hundreds
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Five Digit Number Sara has 10 coins of one thousand each.
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Face Value And Place Value Face Value The face value of a digit is the value of the digit itself at whatever place it may be. For example: In number 6521, Place Value The plac
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Successor and Predecessor Successor The number which comes just after a given number is called its successor. It is obtained by adding 1 to the given number. For example: 5000 is
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NUMBER SYSTEM Introduction In your earlier classes, you have learnt about the number line and how to represent various types of numbers on it (see Fig. 1.1). Just imagine you start from z
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POLYNOMIALS 2.1 Introduction You have studied algebraic expressions, their addition, subtraction, multiplication and division in earlier classes. You also have studied how to factorise som
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COORDINATE GEOMETRY 3.1 Introduction You have already studied how to locate a point on a number line. You also know how to describe the position of a point on the line. There are many other sit
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LINEAR EQUATIONS IN TWO VARIABLES The principal use of the Analytic Art is to bring Mathematical Problems to Equations and to exhibit those Equations in the most simple terms that can be &mdas
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INTRODUCTION TO EUCLID’S GEOMETRY 5.1 Introduction The word ‘geometry’ comes form the Greek words ‘geo’, meaning the ‘earth’, and ‘metrein’
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LINES AND ANGLES 6.1 Introduction In Chapter 5, you have studied that a minimum of two points are required to draw a line. You have also studied some axioms and, with the help of these axi
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TRIANGLES 7.1 Introduction You have studied about triangles and their various properties in your earlier classes. You know that a closed figure formed by three intersecting lines is called a tr
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QUADRILATERALS 8.1 Properties of a Parallelogram You have already studied quadrilaterals and their types in Class VIII. A quadrilateral has four sides, four angles and four vertices. A parallel
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CIRCLES 9.1 Angle Subtended by a Chord at a Point You have already studied about circles and its parts in Class VI. Take a line segment PQ and a point R not on the line containing PQ. Join
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HERON’S FORMULA 10. 1 Area of a Triangle — by Heron’s Formula We know that the area of triangle when its height is given, is \(\frac{1}{2}\) × base × height. Now s
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SURFACE AREAS AND VOLUMES 11.1 Surface Area of a Right Circular Cone We have already studied the surface areas of cube, cuboid and cylinder. We will now study the surface area of cone. So far, w
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STATISTICS 12.1 Graphical Representation of Data The representation of data by tables has already been discussed. Now let us turn our attention to another representation of data, i.e., the grap
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Types Of Numbers Introduction In your earlier classes, you have learnt about the number line and how to represent various types of numbers on it (see Fig. 1.1). Just imagine you
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Rational And Irrational Numbers We saw, in the previous section, that there may be numbers on the number line that are not rationals. In this section, we are going to investigate these numbers. So
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Decimal Expansion Of Real Numbers In this section, we are going to study rational and irrational numbers from a different point of view. We will look at the decimal expansions of real num
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Operations On Real Numbers You have learnt, in earlier classes, that rational numbers satisfy the commutative, associative and distributive laws for addition and multiplication. Moreover,
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POLYNOMIALS Introduction You have studied algebraic expressions, their addition, subtraction, multiplication and division in earlier classes. You also have studied how to factorise some al
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Polynomials in One Variable Let us begin by recalling that a variable is denoted by a symbol that can take any real value. We use the letters x, y, z, etc. to denote variables. Notice that 2
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Zeroes of a Polynomial Consider the polynomial p(x) = \(5{{x}^{3}}-2{{x}^{2}}+3x-2\) If we replace x by 1 everywhere in p(x), we get \( \begin{align} & p\left( 1 \right)=5\times
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Factorisation of Polynomials Let us now look at the situation of Example 10 above more closely. It tells us that since the remainder, \(\left( q-\frac{1}{2} \right)= 0\), (2t + 1) is a factor
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Introduction You have already studied how to locate a point on a number line. You also know how to describe the position of a point on the line. There are many other situations, in which to find a
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Algebraic Identities From your earlier classes, you may recall that an algebraic identity is an algebraic equation that is true for all values of the variables occurring in it. You have studied th
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Cartesian System You have studied the number line in the chapter on ‘Number System’. On the number line, distances from a fixed point are marked in equal units positively in one directi
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Introduction The word ‘geometry’ comes form the Greek words ‘geo’, meaning the ‘earth’, and ‘metrein’, meaning ‘to measure’. Geometry app
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Euclid’s Definitions, Axioms and Postulates The Greek mathematicians of Euclid’s time thought of geometry as an abstract model of the wor
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LINEAR EQUATIONS IN TWO VARIABLES The principal use of the Analytic Art is to bring Mathematical Problems to Equations and to exhibit those Equations in the most simple terms that can be  
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Linear Equations Let us first recall what you have studied so far. Consider the following equation: 2x + 5 = 0 Its solution, i.e., the root of the equation, is −&
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Solution of a Linear Equation You have seen that every linear equation in one variable has a unique solution. What can you say about the solution of a linear equation involving two variables? As t
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Introduction You have studied about triangles and their various properties in your earlier classes. You know that a closed figure formed by three intersecting lines is called a triangle. (‘T
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Congruence of Triangles You must have observed that two copies of your photographs of the same size are identical. Similarly, two bangles of the same size, two ATM cards issued by the same ba
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Introduction In Chapter 5, you have studied that a minimum of two points are required to draw a line. You have also studied some axioms and, with the help of these
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Criteria for Congruence of Triangles In earlier classes, you have learnt four criteria for congruence of triangles. Let us recall them. Draw two triangles with one side 3 cm. Are these triangles co
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Basic Terms and Definitions Recall that a part (or portion) of a line with two end points is called a line-segment and a part of a line with one end point is called a ray. Note that the line segmen
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Intersecting Lines and Non-intersecting Lines Draw two different lines PQ and RS on a paper. You will see that you can draw them in two different ways as shown in Fig. 6.5 (i) and Fig. 6.5 (ii).
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Some Properties of a Triangle In the above section you have studied two criteria for congruence of triangles. Let us now apply these results to study some properties related to a triangle whose tw
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Some More Criteria for Congruence of Triangles You have seen earlier in this chapter that equality of three angles of one triangle to three angles of the other is not sufficient for the congruence
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Pairs of Angles In Section 6.2, you have learnt the definitions of some of the pairs of angles such as complementary angles, supplementary angles, adjacent angles, linear pair of angles, etc. Can y
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Lines Parallel to the Same Line If two lines are parallel to the same line, will they be parallel to each other? Let us check it. See Fig. 6.18 in which line m || line l and line n || line l. &
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Properties of a Parallelogram You have already studied quadrilaterals and their types in Class VIII. A quadrilateral has four sides, four angles and four vertices. A parallelogram is a quadrilatera
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Angle Subtended by a Chord at a Point You have already studied about circles and its parts in Class VI. Take a line segment PQ and a point R not on the line containing PQ. Join PR and QR (see Fig.
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Perpendicular from the Centre to a Chord Activity Draw a circle on a tracing paper. Let O be its centre. Draw a chord AB. Fold the paper along a line through O so that a portion of the chord
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Equal Chords and their Distances from the Centre Let AB be a line and P be a point. Since there are infinite numbers of points on a line, if you join these points to P, you will get infinitely man
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Angle Subtended by an Arc of a Circle You have seen that the end points of a chord other than diameter of a circle cuts it into two arcs – one major and other minor. If you take two equal cho
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Cyclic Quadrilaterals A quadrilateral ABCD is called cyclic if all the four vertices of it lie on a circle (see Fig 9.18). You will find a peculiar property in such quadrilaterals. Draw sev
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HERON’S FORMULA Area of a Triangle — by Heron’s Formula We know that the area of triangle when its height is given, is 12 × base × height. Now suppo
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STATISTICS Graphical Representation of Data The representation of data by tables has already been discussed. Now let us turn our attention to another representation of data, i.e., the graphical
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Surface Area of a Right Circular Cone We have already studied the surface areas of cube, cuboid and cylinder. We will now study the surface area of cone. So
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Surface Area of a Sphere What is a sphere? Is it the same as a circle? Can you draw a circle on a paper? Yes, you can, because a circle is a plane closed figure whose every point lies at a constant
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Volume of a Right Circular Cone In earlier classes we have studied the volumes of cube, cuboid and cylinder Fig 11.11 In Fig 11.11, can you see that there is a right circular cylinder
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Volume of a Sphere Now, let us see how to go about measuring the volume of a sphere. First, take two or three spheres of different radii, and a container big enough to be able to put each of the sp
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Introduction You know that the paper is a model for a plane surface. When you join a number of points without lifting a pencil from the paper (and without retracing any portion of the drawing othe
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Regular and irregular polygons A regular polygon is both ‘equiangular’ and ‘equilateral’. For example, a square has sides of equal length and angles of equal measure.
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Sum of the Measures of the Exterior Angles of a Polygon On many occasions a knowledge of exterior angles may throw light on the nature of interior angles and sides. DO THIS Draw a polygon on
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Kinds of Quadrilaterals Based on the nature of the sides or angles of a quadrilateral, it gets special names. Trapezium Trapezium is a quadrilateral with a pair of parallel sides Stu
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Parallelogram A parallelogram is a quadrilateral. As the name suggests, it has something to do with parallel lines. Study these figures and try to describe in your own words what we mean by
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Angles of a parallelogram We studied a property of parallelograms concerning the (opposite) sides. What can we say about the angles? Property: The opposite angles of a parallelogram are of equa
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Diagonals of a parallelogram The diagonals of a parallelogram, in general, are not of equal length. (Did you check this in your earlier activity?) However, the diagonals of a parallelogram have an
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Some Special Parallelograms Rhombus We obtain a Rhombus (which, you will see, is a parallelogram) as a special case of kite (which is not a a parallelogram). Note that the sides of rhombus
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A rectangle A rectangle is a parallelogram with equal angles (Fig). What is the full meaning of this definition? Discuss with your friends. If the rectangle is to be equiangular,
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A square A square is a rectangle with equal sides. BELT is a square, BE = EL = LT = TB ∠B, ∠E, ∠L, ∠T are right angles. BL = ET and \(\overline{BL}||
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Looking for Information In your day-to-day life, you might have come across information, such as: (a) Runs made by a batsman in the last 10 test matches. (b) Number of wickets taken
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Circle Graph or Pie Chart Have you ever come across data represented in circular form as shown (Fig 4.1)? These are called circle graphs. A circle graph shows the relationship between a who
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Introduction In Mathematics, we frequently come across simple equations to be solved. For example, the equation &n
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Closure Properties of Rational Numbers (i) Whole numbers Let us revisit the closure property for all the operations on whole numbers in brief. Check for closure property under all the fo
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Commutativity Property of Rational Numbers (i) Whole numbers Recall the commutativity of different operations for whole numbers by filling the following table. Check whet
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Associativity Property of Rational Numbers (i) Whole numbers Recall the associativity of the four operations for whole numbers through this table: Fill in this table and
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Chance and Probability Sometimes it happens that during rainy season, you carry a raincoat every day and it does not rain for many days. However, by chance, one day you forget to take the rai
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Equally likely outcomes: A coin is tossed several times and the number of times we get head or tail is noted. Let us look at the result sheet where we keep on increasing the tosses Observe
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Linking chances to probability Consider the experiment of tossing a coin once. What are the outcomes? There are only two outcomes – Head or Tail. Both the outcomes are equally likely. Likelih
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Outcomes as events Each outcome of an experiment or a collection of outcomes make an event. For example in the experiment of tossing a coin, getting a Head is an event and getting a Tail is al
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Chance and probability related to real life We talked about the chance that it rains just on the day when we do not carry a rain coat. What could you say about the chance in terms of probabili
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Introduction You know that the area of a square = side × side (where ‘side’ means ‘the length of a side’). Study the following table What is special about t
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Properties of Square Numbers Following table shows the squares of numbers from 1 to 20 Study the square numbers in the above table. What are the ending digits (that is, digits in the units
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Some More Interesting Patterns 1. Adding triangular numbers. Do you remember triangular numbers (numbers whose dot patterns can be arranged as triangles)? If we combine two consecutive trian
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Finding the Square of a Number And Other patterns in squares Squares of small numbers like 3, 4, 5, 6, 7, ... etc. are easy to find. But can we find the square of 23 so quickly? The answer
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Pythagorean triplets Consider the following\(\) 3\(^2\) + 4\(^2\) = 9 + 16 = 25 = 5\(^2\) The collection of numbers 3, 4 and 5 is known as Pythagorean triplet. 6, 8, 10 is also a Py
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Square Roots Study the following situations. (a) Area of a square is 144 cm2 . What could be the side of the square? We know that the area of a square = side2 If we assume the lengt
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Finding square roots The inverse (opposite) operation of addition is subtraction and the inverse operation of multiplication is division. Similarly, finding the square root is the inverse operatio
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Finding square root through repeated subtraction Finding square root through repeated subtraction Do you remember that the sum of the first n odd natural numbers is n 2 ? Tha
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Finding square root through prime factorisation Consider the prime factorisation of the following numbers and their squares. How many times does 2 occur in the prime factorisation of 6? Onc
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The role of zero (0) Look at the following. 2 + 0 = 0 + 2 = 2 (Addition of 0 to a whole number) – 5 + 0 = ... + ... = – 5 (Addition of 0 to an integer) \(\frac{-2}{7}+...=0+\
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Finding square root by division method When the numbers are large, even the method of finding square root by prime factorisation becomes lengthy and difficult. To overcome this problem we use Long
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Distributivity of multiplication over addition for rational numbers To understand this, consider the rational numbers \(\frac{-3}{4},\frac{2}{3}and\frac{-5}{6}\) \(\frac{-3}{4}\times \left\{ \fr
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Square Roots of Decimals Consider Step 1 To find the square root of a decimal number we put bars on the integral part (i.e., 17) of the number in the usual manner. And place bars on the deci
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Introduction In the earlier classes, you have come across several algebraic expressions and equations. Some examples of expressions we have so far worked with are: 5x, 2x – 3, 3x + y, 2xy
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Solving Equations having the Variable on both Sides An equation is the equality of the values of two expressions. In the equation 2x – 3 = 7, the two expressions are 2x – 3 and 7. In m
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Reducing Equations to Simpler Form Example: Solve \(\frac{6x+1}{3}+1=\frac{x-3}{6}\) Solution: Multiplying both sides of the equation by 6,
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Introduction This is a story about one of India’s great mathematical geniuses, S. Ramanujan. Once another famous mathematician Prof. G.H. Hardy came to visit him in a taxi whose number was 1
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Cubes You know that the word ‘cube’ is used in geometry. A cube is a solid figure which has all its sides equal. How many cubes of side 1 cm will make a cube of side 2 cm? How man
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Some interesting patterns 1.Adding consecutive odd numbers Observe the following pattern of sums of odd numbers. Is it not interesting? How many consecutive odd numbers will be needed to obt
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Smallest multiple that is a perfect cube Raj made a cuboid of plasticine. Length, breadth and height of the cuboid are 15 cm, 30 cm, 15 cm respectively. Anu asks how many such cuboids will she
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Cube Roots If the volume of a cube is 125 cm\(^3\) , what would be the length of its side? To get the length of the side of the cube, we need to know a number whose cube is 125. Finding t
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Introduction We have learnt that for a closed plane figure, the perimeter is the distance around its boundary and its area is the region covered by it. We found the area and perimeter of various p
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Area of a Polygon We split a quadrilateral into triangles and find its area. Similar methods can be used to find the area of a polygon. Observe the following for a pentagon: (Fig 9.1, 9.2)
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Solid Shapes In your earlier classes you have studied that two dimensional figures can be identified as the faces of three dimensional shapes. Observe the solids which we have discussed so fa
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Surface Area of Cube Imran, Monica and Jaspal are painting a cuboidal, cubical and a cylindrical box respectively of same height (Fig 9.4). They try to determine who has painted more area. H
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Surface Area of Cuboid Suppose you cut open a cuboidal box and lay it flat (Fig 9.15). We can see a net as shown below (Fig 9.16). Write the dimension of each side. You know that a cuboid h
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Cylinders Most of the cylinders we observe are right circular cylinders. For example, a tin, round pillars, tube lights, water pipes etc DO THIS (i) Take a cylindrical can or box and trace t
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Volume of Cube Amount of space occupied by a three dimensional object is called its volume. Try to compare the volume of objects surrounding you. For example, volume of a room is greater than the v
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Cuboid Take 36 cubes of equal size (i.e., length of each cube is same). Arrange them to form a cuboid. You can arrange them in many ways. Observe the following table and fill in the blanks.
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Cylinder We know that volume of a cuboid can be found by finding the product of area of base and its height. Can we find the volume of a cylinder in the same way? Just like cuboid, cylinder
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Volume and Capacity There is not much difference between these two words. (a) Volume refers to the amount of space occupied by an object. (b) Capacity refers to the quantity that a contain
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Addition and Subtraction of Algebraic Expressions In earlier classes, we have already become familiar with what algebraic expressions (or simply expressions) are. Examples of expressions are: &
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Multiplication of Algebraic Expressions:Introduction (i) Look at the following patterns of dots &n
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Multiplying a Monomial by a Monomial Expression that contains only one term is called a monomial. Multiplying two monomials : We begin with 4 × x = x + x + x + x = 4x as seen earlier.
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Multiplying a Monomial by a Polynomial Expression that contains two terms is called a binomial. An expression containing three terms is a trinomial and so on. In general, an expression containing,
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Multiplying a Polynomial by a Polynomial Multiplying a binomial by a binomial: Let us multiply one binomial (2a + 3b) by another binomial, say (3a + 4b). We do this step-by-step, as we did in ea
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Introduction Do you know? Mass of earth is 5,970,000,000,000, 000, 000, 000, 000 kg. We have already learnt in earlier class how to write such large numbers more conveniently using exponents, a
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Powers with Negative Exponents You know that, 102 = 10 × 10 = 100 &
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Introduction Mohan prepares tea for himself and his sister. He uses 300 mL of water, 2 spoons of sugar, 1 spoon of tea leaves and 50 mL of milk. How much quantity of each item will he need, if he
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Direct Proportion If the cost of 1 kg of sugar is ₹36, then what would be the cost of 3 kg sugar? It is ₹108. Similarly, we can find the cost of 5 kg or 8 kg of sugar. Study the following t
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Let us consider some solved examples where we would use the concept of direct proportion. Example 1: The cost of 5 metres of a particular quality of cloth is ₹210. Tabulate the cost of
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Inverse Proportion Two quantities may change in such a manner that if one quantity increases, the other quantity decreases and vice versa. For example, as the number of workers increases, time tak
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Example 7: 6 pipes are required to fill a tank in 1 hour 20 minutes. How long will it take if only 5 pipes of the same type are used? Solution: Let the desired time to fill the tank be x minutes.
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Laws of Exponents We have learnt that for any non-zero integer a, a m × a n = a m + n , where m and n are natural numbers. Does this law also hold if the exponents are negative? Let us explor
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Use of Exponents to Express Small Numbers in Standard Form Observe the following facts. 1. The distance from the Earth to the Sun is 149,600,000,000 m. 2. The speed of light is 300,000,000
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Comparing very large and very small numbers The diameter of the Sun is 1.4 × 109 m and the diameter of the Earth is 1.2756 × 107 m. Suppose you want to compare the diameter of the E
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Introduction Factors of natural numbers: You will remember what you learnt about factors in Class VI. Let us take a natural number, say 30, and write it as a product of other natural numbers, sa
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Factors of algebraic expressions We have seen in Class VII that in algebraic expressions, terms are formed as products of factors. For example, in the algebraic expression 5xy + 3x the term 5xy has
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What is Factorisation? When we factorise an algebraic expression, we write it as a product of factors. These factors may be numbers, algebraic variables or algebraic expressions. &n
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Factorisation by regrouping terms Look at the expression 2xy + 2y + 3x + 3. You will notice that the first two terms have common factors 2 and y and the last two terms have a common factor 3. But t
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Factorisation using identities We know that (a + b) 2 = a 2 + 2ab + b 2 (I) &n
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Factors of the form ( x + a) ( x + b) Let us now discuss how we can factorise expressions in one variable, like x 2 + 5x + 6, y 2 – 7y + 12, z 2 – 4z – 12, 3m2 + 9m + 6, etc. Obse
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Division of Algebraic Expressions We have learnt how to add and subtract algebraic expressions. We also know how to multiply two expressions. We have not however, looked at division of one algebrai
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Division of a monomial by another monomial Consider 6x 3 ÷ 2x We may write 2x and 6x 3 in irreducible factor forms, 2x = 2 &tim
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Division of a polynomial by a monomial Let us consider the division of the trinomial 4y 3 + 5y 2 + 6y by the monomial 2y. &
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Division of Algebraic Expressions Continued (Polynomial ÷ Polynomial) • Consider (7x 2 + 14x) ÷ (x + 2) We shall factorise (7x 2 + 14x) first to check and match factors with
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Food Groups and Sources – Carbohydrates, Protiens And Fats Food is one of the basic needs of life. We need food in the same way a car needs fuel. It gives us energy. Our body needs e
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Introduction Have you seen graphs in the newspapers, television, magazines, books etc.? The purpose of the graph is to show numerical facts in visual form so that they can be understood quickly, e
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Introduction Have you seen graphs in the newspapers, television, magazines, books etc.? The purpose of the graph is to show numerical facts in visual form so that they can be understood quickly, e
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Vitamins, Minerals And Water Vitamins Vitamins are needed in small amounts for the normal functioning of our body. They help in keeping our eyes, bones, teeth and gums healthy. Unlike carbohydra
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Example 1: (A graph on “performance”) The given graph (Fig 13.3) represents the total runs scored by two batsmen A and B, during each of the ten different matches in the year 2007. Study t
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Balanced Diet And Unbalanced Diet Balanced Diet and its Importance We eat different types of food everyday. These may be wheat, rice, pulses, vegetables, fruits, meat, milk, curd, etc. which con
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Some Applications In everyday life, you might have observed that the more you use a facility, the more you pay for it. If more electricity is consumed, the bill is bound to be high. If less e
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Example : (Principal and Simple Interest) A bank gives 10% Simple Interest (S.I.) on deposits by senior citizens. Draw a graph to illustrate the relation between the sum deposited and simple interest
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Food Pyramid A food pyramid is a chart that helps us in choosing our daily food. It shows food which we should eat from each group everyday. The food pyramid helps people to select foods that supp
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Personal Hygiene Personal hygiene may be described as the principle of maintaining cleanliness of the body parts like head, hair, ears, face, eyes, nose, neck, teeth, hands, feet and skin Basic
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Example : (Time and Distance) Ajit can ride a scooter constantly at a speed of 30 kms/hour. Draw a time-distance graph for this situation. Use it to find (i) the time taken by Ajit to ride 75 km.
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Recalling Ratios and Percentages We know, ratio means comparing two quantities. A basket has two types of fruits, say, 20 apples and 5 oranges. Then, the ratio of the number of oranges to the
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Finding Discounts Discount is a reduction given on the Marked Price (MP) of the article. This is generally given to attract customers to buy goods or to promote sales of the goods. You can find th
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Sales Tax/Value Added Tax/Goods and Services Tax The teacher showed the class a bill in which the following heads were written. Sales tax (ST) is charged by the government on the sale of an ite
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Compound Interest You might have come across statements like “one year interest for FD (fixed deposit) in the bank @ 9% per annum” or ‘Savings account with interest @ 5% per annu
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Deducing a Formula for Compound Interest Zubeda asked her teacher, ‘Is there an easier way to find compound interest?’ The teacher said ‘There is a shorter way of finding compoun
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Applications of Compound Interest Formula There are some situations where we could use the formula for calculation of amount in CI. Here are a few. (i) Increase (or decrease) in populatio
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PROPERTIES OF ADDITION AND SUBTRACTION OF INTEGERS We have learnt about whole numbers and integers in Class VI. We have also learnt about addition and subtraction of integers. Closure under Add
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MULTIPLICATION OF INTEGERS We can add and subtract integers. Let us now learn how to multiply integers. Multiplication of a Positive and a Negative Integer We know that multipl
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PROPERTIES OF MULTIPLICATION OF INTEGERS Closure under Multiplication 1. Observe the following table and complete it: What do you observe? Can you find a pair of integers whose product
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DIVISION OF INTEGERS We know that division is the inverse operation of multiplication. Let us see an example for whole numbers. Since 3 × 5 = 15 So 15 ÷ 5 = 3 and 15 &divi
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MULTIPLICATION OF FRACTIONS You know how to find the area of a rectangle. It is equal to length × breadth. If the length and breadth of a rectangle are 7 cm and 4 cm respectively, then what w
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Multiplication of a Fraction by a Fraction Farida had a 9 cm long strip of ribbon. She cut this strip into four equal parts. How did she do it? She folded the strip twice. What fraction of the tota
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REPRESENTATIVE VALUES You might be aware of the term average and would have come across statements involving the term ‘average’ in your day-to-day life: Isha spends on an ave
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ARITHMETIC MEAN The most common representative value of a group of data is the arithmetic mean or the mean. To understand this in a better way, let us look at the following example: Two vessels co
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MODE As we have said Mean is not the only measure of central tendency or the only form of representative value. For different requirements from a data, other measures of central tendencies are use
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MEDIAN We have seen that in some situations, arithmetic mean is an appropriate measure of central tendency whereas in some other situations, mode is the appropriate measure of central tendency. Le
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USE OF BAR GRAPHS WITH A DIFFERENT PURPOSE We have seen last year how information collected could be first arranged in a frequency distribution table and then this information could be put as a vi
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A MIND-READING GAME! The teacher has said that she would be starting a new chapter in mathematics and it is going to be simple equations. Appu, Sarita and Ameena have revised what they learnt in a
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REVIEW OF WHAT WE KNOW Note, (4.1) and (4.2) are equations. Let us recall what we learnt about equations in Class VI. An equation is a condition on a variable. In equation (4.1), the variable is x
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SETTING UP OF AN EQUATION Let us take Ameena’s example. Ameena asks Sara to think of a number. Ameena does not know the number. For her, it could be anything 1, 2, 3, . . ., 11, . . . , 100,
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WHAT EQUATION IS? In an equation there is always an equality sign. The equality sign shows that the value of the expression to the left of the sign (the left hand side or LHS) is equal to the valu
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Solving an Equation Consider an equality 8 – 3 = 4 + 1…….. (4.5) The equality (4.5) holds, since both its sides are equal (each is equal to 5) * Let us now add
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APPLICATIONS OF SIMPLE EQUATIONS TO PRACTICAL SITUATIONS We have already seen examples in which we have taken statements in everyday language and converted them into simple equations. We also have
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DIVISION OF FRACTIONS John has a paper strip of length 6 cm. He cuts this strip in smaller strips of length 2 cm each. You know that he would get 6 ÷ 2 =3 strips. John cuts another strip
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Division of a Fraction by a Whole Number What will be ÷ 3? Based on our earlier observations we have: \(\frac{3}{4}\) ÷ 3 = \(\frac{3}{4}\
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MULTIPLICATION OF DECIMAL NUMBERS Reshma purchased 1.5kg vegetable at the rate of ₹8.50 per kg. How much money should she pay? Certainly it would be ₹ (8.50 × 1.50). Both 8.5 and 1.5 are
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Multiplication of Decimal Numbers by 10, 100 and 1000 Reshma observed that 2.3 = \(\frac{23}{10}\) whereas 2.35 = \(\frac{235}{10}\). Thus, she found that depending on the position of the decimal
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DIVISION OF DECIMAL NUMBERS Savita was preparing a design to decorate her classroom. She needed a few coloured strips of paper of length 1.9 cm each. She had a strip of coloured paper of length 9.5
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Division of a Decimal Number by a Whole Number Let us find \(\frac{6.4}{2}\). Remember we also write it as 6.4 ÷ 2. So, 6.4 ÷ 2 = \(\frac{64}{10}\) ÷ 2 = \(\frac{64}{10}\ti
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Division of a Decimal Number by another Decimal Number Let us find \(\frac{25.5}{0.5}\) i.e., 25.5 ÷ 0.5. We have \(\frac{255}{10}\div \frac{5}{10}=\frac{255}{10}\times \frac{10}{5}=51\)
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INTRODUCTION A triangle, you have seen, is a simple closed curve made of three line segments. It has three vertices, three sides and three angles. Here is ∆ABC (Fig 6.1). It has Sides: \(
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MEDIANS OF A TRIANGLE Given a line segment, you know how to find its perpendicular bisector by paper folding. Cut out a triangle ABC from a piece of paper (Fig 6.3). Consider any one of its s
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ALTITUDES OF A TRIANGLE Make a triangular shaped cardboard ABC. Place it upright on a table. How ‘tall’ is the triangle? The height is the distance from vertex A (in the Fig 6.4)
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EXTERIOR ANGLE OF A TRIANGLE AND ITS PROPERTY DO THIS 1.Draw a triangle ABC and produce one of its sides, say BC as shown in Fig 6.7. Observe the angle ACD formed at the point C. This angle lies
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ANGLE SUM PROPERTY OF A TRIANGLE There is a remarkable property connecting the three angles of a triangle. You are going to see this through the following four activities. 1. Draw a triangle.
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TWO SPECIAL TRIANGLES : EQUILATERAL AND ISOSCELES A triangle in which all the three sides are of equal lengths is called an equilateral triangle. Take two copies of an equilateral triangle AB
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SUM OF THE LENGTHS OF TWO SIDES OF A TRIANGLE 1. Mark three non-collinear spots A, B and C in your playground. Using lime powder mark the paths AB, BC and AC. Ask your friend to start from A an
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RIGHT-ANGLED TRIANGLES AND PYTHAGORAS PROPERTY Pythagoras, a Greek philosopher of sixth century B.C. is said to have found a very important and useful property of right-angled triangles given in t
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PERCENTAGE – ANOTHER WAY OF COMPARING QUANTITIES Anita said that she has done better as she got 320 marks whereas Rita got only 300. Do you agree with her? Who do you think has done bette
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Converting Fractional Numbers to Percentage Fractional numbers can have different denominator. To compare fractional numbers, we need a common denominator and we have seen that it is more con
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Converting Decimals to Percentage We have seen how fractions can be converted to per cents. Let us now find how decimals can be converted to per cents. EXAMPLE Convert the given decim
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INTRODUCTION You already know how to identify different lines, line segments and angles in a given shape. Can you identify the different line segments and angles formed in the following figures? (F
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Fun with Estimation Percentages help us to estimate the parts of an area. EXAMPLE : What per cent of the adjoining figure is shaded? SOLUTION :We first find the fraction of
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USE OF PERCENTAGES Interpreting Percentages We saw how percentages were helpful in comparison. We have also learnt to convert fractional numbers and decimals to percentages. Now, we shall lear
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Converting Percentages to “How Many” Consider the following examples: EXAMPLE : A survey of 40 children showed that 25% liked playing football. How many children liked playing
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RELATED ANGLES Complementary Angles : When the sum of the measures of two angles is 90°, the angles are called complementary angles. (i) (ii)
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Ratios to Percents Sometimes, parts are given to us in the form of ratios and we need to convert those to percentages. Consider the following example: EXAMPLE : Reena’s mother said, to ma
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PAIRS OF LINES Intersecting Lines: &nbs
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Increase or Decrease as Per Cent There are times when we need to know the increase or decrease in a certain quantity as percentage. For example, if the population of a state increased from 5,50,000 to
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PRICES RELATED TO AN ITEM OR BUYING AND SELLING The buying price of any item is known as its cost price. It is written in short as CP. The price at which you sell is known as the selling pr
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Profit or Loss as a Percentage The profit or loss can be converted to a percentage. It is always calculated on the CP. For the above examples, we can find the profit % or loss %. Let us co
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CHARGE GIVEN ON BORROWED MONEY OR SIMPLE INTEREST Sohini said that they were going to buy a new scooter. Mohan asked her whether they had the money to buy it. Sohini said her father was going to t
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Interest for Multiple Years If the amount is borrowed for more than one year the interest is calculated for the period the money is kept for. For example, if Anita returns the money at the end of t
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CHECKING FOR PARALLEL LINES If two lines are parallel, then you know that a transversal gives rise to pairs of equal corresponding angles, equal alternate interior angles and interior angles on the
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AREA OF A PARALLELOGRAM We come across many shapes other than squares and rectangles. How will you find the area of a land which is a parallelogram in shape? Let us find a method to get the area o
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AREA OF A TRIANGLE A gardener wants to know the cost of covering the whole of a triangular garden with grass. In this case we need to know the area of the triangular region. Let us fin
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INTRODUCTION You began your study of numbers by counting objects around you. The numbers used for this purpose were called counting numbers or natural numbers. They are 1, 2, 3, 4, ... By including
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CIRCLES A racing track is semi-circular at both ends (Fig 9.18). Can you find the distance covered by an athlete if he takes two rounds of a racing track? We need to find a method to find
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NEED FOR RATIONAL NUMBERS Earlier, we have seen how integers could be used to denote opposite situations involving numbers. For example, if the distance of 3 km to the right of a place was denoted
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Area of Circle Consider the following: A farmer dug a flower bed of radius 7 m at the centre of a field. He needs to purchase fertiliser. If 1 kg of fertiliser is required for 1 square metre
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INTRODUCTION We have already come across simple algebraic expressions like x + 3, y – 5, 4x + 5, 10y – 5 and so on. In Class VI, we have seen how these expressions are useful in formula
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TERMS OF AN EXPRESSION We shall now put in a systematic form what we have learnt above about how expressions are formed. For this purpose, we need to understand what terms of an expression and the
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WHAT ARE RATIONAL NUMBERS? The word ‘rational’ arises from the term ‘ratio’. You know that a ratio like 3:2 can also be written as \(\frac{3}{2}\) . Here, 3 and 2 are natura
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POSITIVE AND NEGATIVE RATIONAL NUMBERS Consider the rational number \(\frac{2}{3}\) . Both the numerator and denominator of this number are positive integers. Such a rational number is called a pos
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RATIONAL NUMBERS ON A NUMBER LINE The points to the right of 0 are denoted by + sign and are positive integers. The points to the left of 0 are denoted by – sign and are negative integers
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RATIONAL NUMBERS IN STANDARD FORM Observe the rational numbers \(\frac{3}{5},\frac{-5}{8},\frac{2}{7},\frac{-7}{11}\). The denominators of these rational nu
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COMPARISON OF RATIONAL NUMBERS We know how to compare two integers or two fractions and tell which is smaller or which is greater among them. Let us now see how we can compare two rational numbers.
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COMPARISON OF RATIONAL NUMBERS We know how to compare two integers or two fractions and tell which is smaller or which is greater among them. Let us now see how we can compare two rational numbers.
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COMPARISON OF RATIONAL NUMBERS We know how to compare two integers or two fractions and tell which is smaller or which is greater among them. Let us now see how we can compare two rational numbers.
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COMPARISON OF RATIONAL NUMBERS We know how to compare two integers or two fractions and tell which is smaller or which is greater among them. Let us now see how we can compare two rational numbers.
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COMPARISON OF RATIONAL NUMBERS We know how to compare two integers or two fractions and tell which is smaller or which is greater among them. Let us now see how we can compare two rational numbers.
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COMPARISON OF RATIONAL NUMBERS We know how to compare two integers or two fractions and tell which is smaller or which is greater among them. Let us now see how we can compare two rational numbers.
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COMPARISON OF RATIONAL NUMBERS We know how to compare two integers or two fractions and tell which is smaller or which is greater among them. Let us now see how we can compare two rational numbers.
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COMPARISON OF RATIONAL NUMBERS We know how to compare two integers or two fractions and tell which is smaller or which is greater among them. Let us now see how we can compare two rational numbers.
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RATIONAL NUMBERS BETWEEN TWO RATIONAL NUMBERS Reshma wanted to count the whole numbers between 3 and 10. From her earlier classes, she knew there would be exactly 6 whole numbers between 3 and 10.
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OPERATIONS ON RATIONAL NUMBERS You know how to add, subtract, multiply and divide integers as well as fractions. Let us now study these basic operations on rational numbers. Addition: Let us
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LIKE AND UNLIKE TERMS When terms have the same algebraic factors, they are like terms. When terms have different algebraic factors, they are unlike terms. For example, in the expression 2xy &ndash
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MONOMIALS, BINOMIALS, TRINOMIALS AND POLYNOMIALS An expression with only one term is called a monomial; for example, 7xy, – 5m, 3z 2 , 4 etc. An expression which contains two unlike ter
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FINDING THE VALUE OF AN EXPRESSION We know that the value of an algebraic expression depends on the values of the variables forming the expression. There are a number of situations in which we nee
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INTRODUCTION Symmetry is an important geometrical concept, commonly exhibited in nature and is used almost in every field of activity. Artists, professionals, designers of clothing or jewellery, ca
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LINES OF SYMMETRY FOR REGULAR POLYGONS You know that a polygon is a closed figure made of several line segments. The polygon made up of the least number of line segments is the triangle. (Can ther
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ROTATIONAL SYMMETRY What do you say when the hands of a clock go round? You say that they rotate. The hands of a clock rotate in only one direction, about a fixed point, the centre of the clock-fa
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LINE SYMMETRY AND ROTATIONAL SYMMETRY You have been observing many shapes and their symmetries so far. By now you would have understood that some shapes have only line symmetry, some have only rot
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INTRODUCTION: PLANE FIGURES AND SOLID SHAPES In this chapter, you will classify figures you have seen in terms of what is known as dimension. In our day to day life, we see several objects lik
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FACES, EDGES AND VERTICES Do you remember the Faces, Vertices and Edges of solid shapes, which you studied earlier? Here you see them for a cube: The 8 corners of the cube are its vertices.
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INTRODUCTION Do you know what the mass of earth is? It is 5,970,000,000,000,000,000,000,000 kg! Can you read this number? Mass of Uranus is 86,800,000,000,000,000,000,000,000 kg. Which
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NETS FOR BUILDING 3-D SHAPES Take a cardboard box. Cut the edges to lay the box flat. You have now a net for that box. A net is a sort of skeleton-outline in 2-D [Fig13.4 (i)], which, when folded
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DRAWING SOLIDS ON A FLAT SURFACE Your drawing surface is paper, which is flat. When you draw a solid shape, the images are somewhat distorted to make them appear three-dimensional. It is a visual
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Isometric Sketches Have you seen an isometric dot sheet? (A sample is given at the end of the book). Such a sheet divides the paper into small equilateral triangles made up of dots or lines. To dr
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EXPONENTS We can write large numbers in a shorter form using exponents. Observe 10, 000 = 10 × 10 × 10 × 10 = 104 The short notation 1
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LAWS OF EXPONENTS Multiplying Powers with the Same Base: (i) Let us calculate 22 × 23 2 2 × 23 = (2 × 2) × (2 × 2 × 2) &
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Dividing Powers with the Same Base Let us simplify 37 ÷ 34 ? \({{3}^{7}}\div {{3}^{4}}=\frac{{{3}^{7}}}{{{3}^{4}}}=\frac{3\text{ }\times 3\times 3\times 3\times 3\times 3\times 3}{3\text{
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Taking Power of a Power Consider the following Simplify \({{({{2}^{3}})}^{2}};{{({{3}^{2}})}^{4}}\) Now, \({{({{2}^{3}})}^{2}}\) means 23 is multiplied two times with itself. \({{({
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Multiplying Powers with the Same Exponents Can you simplify 23 × 33 ? Notice that here the two terms 23 and 33 have different bases, but the same exponents. Now, 2 3 × 33 = (2
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Dividing Powers with the Same Exponents Observe the following simplifications: (i)\(\frac{{{2}^{4}}}{{{3}^{4}}}=\frac{2\times 2\times 2\times 2}{3\times 3\times 3\times 3}=\frac{2}{3}\times \fra
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Ascending order Look at these numbers. Which is the smallest number? Which is the biggest number? The smallest number is written first. The biggest number is written at the
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Descending order Look at these numbers. Which is the smallest number? Which is the biggest number? The biggest number is written first. The smallest number is written at the
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Visualising Solid Objects Here are some activities you could try in your free time to help you visualise some solid objects and how they look. Take some cubes and arrange them as shown in Fig 13.16
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One Way to View an Object is by Cutting or Slicing Slicing game Here is a loaf of bread (Fig 13.20). It is like a cuboid with a square face. You ‘slice’ it with a knife. When y
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Another Way is by Shadow Play A shadow play Shadows are a good way to illustrate how three-dimensional objects can be viewed in two dimensions. Have you seen a shadow play? It is a form o
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A Third Way is by Looking at it from Certain Angles to Get Different Views One can look at an object standing in front of it or by the side of it or from above. Each time one will get a different
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MISCELLANEOUS EXAMPLES USING THE LAWS OF EXPONENTS Let us solve some examples using rules of exponents developed. EXAMPLE Write exponential form for 8 × 8 × 8 × 8 taking
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DECIMAL NUMBER SYSTEM Let us look at the expansion of 47561, which we already know: 47561 = 4 × 10000 + 7 × 1000 + 5 × 100 + 6 × 10 + 1 We can express it using powe
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EXPRESSING LARGE NUMBERS IN THE STANDARD FORM Let us now go back to the beginning of the chapter. We said that large numbers can be conveniently expressed using exponents. We have not as yet shown
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Introduction Counting things is easy for us now. We can count objects in large numbers, for example, the number of students in the school, and represent them through numerals. We can also communica
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Comparing Numbers As we have done quite a lot of this earlier, let us see if we remember which is the greatest among these : (i) 92, 392, 4456, 89742 (ii) 1902, 1920, 9201, 9021, 9210 So,
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How many numbers can you make? Suppose, we have four digits 7, 8, 3, 5. Using these digits we want to make different 4-digit numbers in such a way that no digit is repeated in them. Thus, 7835 is
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Shifting digits Have you thought what fun it would be if the digits in a number could shift (move) from one place to the other? Think about what would happ
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Introducing 10,000 We know that beyond 99 there is no 2-digit number. 99 is the greatest 2-digit number. Similarly, the greatest 3-digit number is 999 and the greatest 4-digit number is 9999. What
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Revisiting place value You have done this quite earlier, and you will certainly remember the expansion of a 2-digit number like 78 as 78 = 70 + 8 = 7 × 10
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Introducing 1,00,000 Which is the greatest 5-digit number? Adding 1 to the greatest 5-digit number, should give the smallest 6-digit number : 99,999 + 1 = 1,0
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Larger numbers If we add one more to the greatest 6-digit number we get the smallest 7-digit number. It is called ten lakh. Write down the gr
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An aid in reading and writing large numbers Try reading the following numbers : (a) 279453 (b) 5035472 (c) 152700375 (d) 40350894 Was it difficult? Did you find
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Large Numbers in Practice In earlier classes, we have learnt that we use centimetre (cm) as a unit of length. For measuring the length of a pencil, the width of a book or notebooks etc., we use ce
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Predecessor and successor Given any natural number, you can add 1 to that number and get the next number i.e. you get its successor. The successor of 16 is 16 + 1 = 17, that of 19 is 19 +1 = 20
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Whole Numbers We have seen that the number 1 has no predecessor in natural numbers. To the collection of natural numbers we add zero as the predecessor for 1. The natural numbers along with zer
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The Number Line Draw a line. Mark a point on it. Label it 0. Mark a second point to the right of 0. Label it 1. The distance between these points labelled as 0 and 1 is called unit distance. On th
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Introduction Geometry has a long and rich history. The term ‘Geometry’ is the English equivalent of the Greek word ‘Geometron’. ‘Geo’ means Earth and ‘metr
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Points By a sharp tip of the pencil, mark a dot on the paper. Sharper the tip, thinner will be the dot. This almost invisible tiny dot will give you an idea of a point. A point determines a
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A Line Segment Fold a piece of paper and unfold it. Do you see a fold? This gives the idea of a line segment. It has two end points A and B. Take a thin thread. Hold its two ends and
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A Line Imagine that the line segment from A to B (i.e. \(\overline{AB}\)) is extended beyond A in one direction and beyond B in the other direction without any end (see figure). You now get a
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Intersecting Lines Look at the diagram (Fig 4.4). Two lines \(l_1\) and \(l_2\) are shown. Both the lines pass through point P. We say \(l_1\) and \(l_2\)intersect at P. If t
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Parallel Lines Let us look at this table (Fig 4.6). The top ABCD is flat. Are you able to see some points and line segments? Are there intersecting line segments? Yes, AB and BC inter
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Introduction Ramesh has 6 marbles with him. He wants to arrange them in rows in such a way that each row has the same number of marbles. He arranges them in the following ways and matches the total
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Curves Have you ever taken a piece of paper and just doodled? The pictures that are results of your doodling are called curves You can draw some of these drawings without lifting the pencil
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Polygons Look at these figures 4.13 (i), (ii), (iii), (iv), (v) and (vi). What can you say? Are they closed? How does each one of them differ from the other? (i), (ii), (iii), (iv) and
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Angles Angles are made when corners are formed. Here is a picture (Fig 4.16) where the top of a box is like a hinged lid. The edges AD of the box and AP of the door can be imagined as two r
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Factors And Multiples Mary wants to find those numbers which exactly divide 4. She divides 4 by numbers less than 4 this way
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Prime and Composite Numbers We are now familiar with the factors of a number. Observe the number of factors of a few numbers arranged in this table. We find that (a) The number 1 has on
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Tests for Divisibility of Numbers Is the number 38 divisible by 2? by 4? by 5? By actually dividing 38 by these numbers we find that it is divisible by 2 but
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Common Factors and Common Multiples Observe the factors of some numbers taken in pairs. (a) What are the factors of 4 and 18? The factors of 4 are 1, 2 and 4. &
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Prime Factorisation When a number is expressed as a product of its factors we say that the number has been factorised. Thus, when we write 24 = 3×8, we say that 24 has been factorised. This
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Highest Common Factor We can find the common factors of any two numbers. We now try to find the highest of these common factors. What are the common factors of 12 and 16? They are 1, 2 and 4.
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Lowest Common Multiple What are the common multiples of 4 and 6? They are 12, 24, 36, ... . Which is the lowest of these? It is 12. We say that lowest common multiple of 4 and 6 is 12. It is the s
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Some Problems on HCF and LCM We come across a number of situations in which we make use of the concepts of HCF and LCM. We explain these situations through a few examples. Example 12 : Two tan
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Introduction Sunita’s mother has 8 bananas. Sunita has to go for a picnic with her friends. She wants to carry 10 bananas with her. Can her mother give 10 bananas to her? She does not have en
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Tag me with a sign We have seen that some numbers carry a minus sign. For example, if we want to show Ronald’s due amount to the shopkeeper we would write it as – 3. Following is an
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Let us understand this by the following figures. Let us suppose that the figures represent the collection of numbers written against them. Natural numbers Zero&nb
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Representation of integers on a number line Draw a line and mark some points at equal distance on it as shown in the figure. Mark a point as zero on it. Points to the right of zero are positive
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Ordering of integers Raman and Imran live in a village where there is a step well. There are in all 25 steps down to the bottom of the well. One day Raman and Im
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Introduction All the shapes we see around us are formed using curves or lines. We can see corners, edges, planes, open curves and closed curves in our surroundings. We organise them into line segme
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Right And Straight Angles You have heard of directions in Geography. We know that China is to the north of India, Sri Lanka is to the south. We also know that Sun rises in the east and sets in the
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Acute Obtuse and Reflex Angles We saw what we mean by a right angle and a straight angle. However, not all the angles we come across are one of these two kinds. The angle made by a ladder
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Measuring Angles The improvised ‘Right-angle tester’ we made is helpful to compare angles with a right angle. We were able to classify the angles as acute, obtuse or reflex. But this d
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Perpendicular Lines When two lines intersect and the angle between them is a right angle, then the lines are said to be perpendicular. If a line AB is perpendicular to CD, we write AB⊥ CD &nb
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Classification of Triangles Do you remember a polygon with the least number of sides? That is a triangle. Let us see the different types of triangle we can get. Take some more triangles an
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Quadrilaterals A quadrilateral, if you remember, is a polygon which has four sides. (a) Both of you will have a pair of 30°– 60°– 90° set-squares. Place them as sho
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Polygons So far you studied polygons of 3 or 4 sides (known as triangles and quardrilaterals respectively). We now try to extend the idea of polygon to figures with more number of sides. We may cl
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Addition of Integers Do This (Going up and down) In Mohan’s house, there are stairs for going up to the terrace and for going down to the godown. Let us consider the number of stai
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Addition of integers on a number line It is not always easy to add integers using coloured buttons. Shall we use number line for additions? (i) Let us add 3 and 5 on number line. Fig 6
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Subtraction of Integers with the help of a Number Line We have added positive integers on a number line. For example, consider 6+2. We start from 6 and go 2 steps to
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Introduction You must have observed your teacher recording the attendance of students in your class everyday, or recording marks obtained by you after every test or examination. Similarly, you must
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Recording Data Let us take an example of a class which is preparing to go for a picnic. The teacher asked the students to give their choice of fruits out of banana, apple, orange or guava. Uma is
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Organisation of Data To get the same information which Salma got, Ronald needs only a pen and a paper. He does not need pebbles. He also does not ask students to come and place the pebbles. He pre
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Pictograph A cupboard has five compartments. In each compartment a row of books is arranged. The details are indicated in the adjoining table : &nbs
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Interpretation of a Pictograph Example 3 : The following pictograph shows the number of absentees in a class of 30 students during the previous week : (a) On which day were the maximum numb
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Introduction When we talk about some plane figures as shown below we think of their regions and their boundaries. We need some measures to compare them. We look into these now.  
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Introduction Subhash had learnt about fractions in Classes IV and V, so whenever possible he would try to use fractions. One occasion was when he forgot his lunch at home. His friend Farida invited
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A Fraction Let us recapitulate the discussion. A fraction means a part of a group or of a region. \(5\over 12\) is a fraction. We read it as “five-twelfths”. What does “12&rd
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Fraction on the Number Line You have learnt to show whole numbers like 0,1,2... on a number line. We can also show fractions on a number line. Let us draw a number line and try to mark&nb
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Proper Fractions You have now learnt how to locate fractions on a number line. Locate the fractions \(3 \over 4\) ,\(1\over 2\) ,\(9\over 10\) ,\(0 \over 3\) ,\(5\over 8\)
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Improper and Mixed Fractions Anagha, Ravi, Reshma and John shared their tiffin. Along with their food, they had also, brought 5 apples. After eating the other food, the four friends wanted to eat
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Equivalent Fractions Look at all these representations of fraction (Fig 7.10) These fractions are \(1 \over 2\) ,\(2 \over 4\) ,\(3\over 6\) representing the parts taken fro
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Simplest Form of a Fraction Given the fraction \(36\over 54\) , let us try to get an equivalent fraction in which the numerator and the denominator have no common factor except 1. How do
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Like Fractions Fractions with same denominators are called like fractions. Thus \(\frac{1}{15},\frac{2}{15},\frac{3}{15},\frac{8}{15}\) are all like fractions. Are \(7 \over 27\) and&nbs
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Comparing Fractions Sohni has 3\(\frac{1}{2}\) rotis in her plate and Rita has 2\(3 \over 4\) rotis in her plate. Who has more rotis in her plate? Clearly, Sohni has 3 full rotis and mor
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Comparing like fractions Like fractions are fractions with the same denominator. Which of these are like fractions? \(\frac{2}{5},\frac{3}{4},\frac{1}{5},\frac{7}{2},\frac{3}{5},\frac{4}{5
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Perimeter Look at the following figures (Fig. 10.1). You can make them with a wire or a string. If you start from the point S in each case and move along the line se
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Perimeter of a rectangle Let us consider a rectangle ABCD (Fig 10.2) whose length and breadth are 15 cm and 9 cm respectively. What will be its perimeter? Fig 10.2 Perimeter of the rectangl
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Perimeter of regular shapes Consider this example. Biswamitra wants to put coloured tape all around a square picture (Fig 10.5) of side 1m as shown. What wi
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Comparing unlike fractions Two fractions are unlike if they have different denominators. For example, \(\frac{1}{3}\) and \(\frac{1}{5}\) are unlike fractions. So are 2 3 and 3 5 . Un
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Why LCM? The product of 6 and 15 is 90; obviously 90 is also a common multiple of 6 and 15. We may use 90 instead of 30; it will not be wrong. But we know that it is easier and more convenient to
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Area Look at the closed figures (Fig 10.8) given below. All of them occupy some region of a flat surface. Can you tell which one occupies more region? (a) (b) &n
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Addition and Subtraction of Fractions So far in our study we have learnt about natural numbers, whole numbers and then integers. In the present chapter, we are learning about fractions, a dif
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Area of a rectangle With the help of the squared paper, can we tell, what will be the area of a rectangle whose length is 5 cm and breadth is 3 cm? Dr
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Area of a square Let us now consider a square of side 4 cm (Fig 10.14). Fig 10.14 What will be its area? If we place it on a cent
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Adding or subtracting like fractions All fractions cannot be added orally. We need to know how they can be added in different situations and learn the procedure for it. We begin by looking at addi
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Adding and subtracting fractions We have learnt to add and subtract like fractions. It is also not very difficult to add fractions that do not have the same denominator. When we have to add or sub
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Introduction Savita and Shama were going to market to buy some stationary items. Savita said, “I have 5 rupees and 75 paise”. Shama said, “I have 7 rupees and 50 paise”.
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Comparing Decimals Can you tell which is greater, 0.07 or 0.1? Take two pieces of square papers of the same size. Divide them into 100 equal parts. F
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Introduction Our study so far has been with numbers and shapes. We have learnt numbers, operations on numbers and properties of numbers. We applied our knowledge of numbers to various problems in o
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Using Decimals Money : We know that 100 paise = ₹1 Therefore, 1 paise = ₹\(\frac{1}{100}\)= ₹ 0.01 So, 65 paise = ₹\(\frac{65}{100}\) = ₹0.65 and 5 paise = ₹\(\frac{5}{10
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Matchstick Patterns Ameena and Sarita are making patterns with matchsticks. They decide to make simple patterns of the letters of the English alphabet. Ameena takes two matchsticks and forms the l
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Weight Nandu bought 500g potatoes, 250g capsicum, 700g onions, 500g tomatoes, 100g ginger and 300g radish. What is the total weight of the vegetables in the bag? Let us add the weight of all the v
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The Idea of a Variable In the above example, we found a rule to give the number of matchsticks required to make a pattern of Ls. The rule was : Number of matchsticks required = 2n &nbs
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More Matchstick Patterns Ameena and Sarita have become quite interested in matchstick patterns. They now want to try a pattern of the letter C. To make one C, they use three matchsticks as shown i
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More Examples of Variables We have used the letter n to show a variable. Raju asks, “Why not m”? There is nothing special about n, any letter can be used. Let us now consider va
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Introduction In our daily life, many a times we compare two quantities of the same type. For example, Avnee and Shari collected flowers for scrap notebook. Avnee collected 30 flowers and Shari coll
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Addition of Numbers with Decimals Do This Add 0.35 and 0.42. Take a square and divide it into 100 equal parts. Mark 0.35 in this square by shading 3 tenths and colouring 5 hundred
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Ratio Consider the following: Isha’s weight is 25 kg and her father’s weight is 75 kg. How many times Father’s weight is of Isha’s weight? It is three times. Cost of a
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Same ratio in different situations : Consider the following : ● Length of a room is 30 m and its breadth is 20 m. So, the ratio of length of the room to the breadth of the room = \
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Sharing a ratio means something! Consider the following examples : ● Raj purchased 3 pens for ₹15 and Anu purchased 10 pens for ₹50. Whose pens are more expensive? Ratio
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Proportion Consider this situation : Raju went to the market to purchase tomatoes. One shopkeeper tells him that the cost of tomatoes is ₹40 for 5 kg. Another shopkeeper gives the cost as 6
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Unitary Method Consider the following situations: ● Two friends Reshma and Seema went to market to purchase notebooks. Reshma purchased 2 notebooks for ₹24. What is the price of one notebo
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आपका स्वागत है “हिंदी निबंध” पर, जहां आपको सरल भाषा में विविध विषयों पर ले
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చార్లెస్ డార్విన్:- ఈయనకు ఆహారము విషయములో చాలా ప్రత్యేకతలు ఉన్నాయి అయన ప్
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Even And Odd Numbers Natural numbers : The counting numbers are known as natural numbers. Ex : 1, 2, 3, 4, 5 .............. Whole numbers : The natural numbers together with ‘0’ are
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Multiples And Factors Introduction: * If a number ‘a’ divides another number ‘b’ exactly then we say that ‘b’ is called multiple of &lsq
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Prime And Composite Numbers Observe the number of factors of some numbers arranged in the following table Number Factors Number of factors
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INTRODUCTION: “MEASUREMENT” is the determination of the size or magnitude of something. Measurement can also be defined as “Comparison of an unknown quantity with some known quantit
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DEFINITIONS FOR S.I. UNITS: Fundamental quantities Meter: The distance travelled by light in vacuum in 1 in 299, 792, 458th second is called meter. Kilogram: kilogram is the mass of a platinum - ir
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The things or objects, which we all use in our daily life are made up of different types of materials Examples: Pen, Book, Chair etc.... Material is a substance that is used for making things.
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MATTER: Any material which has mass and occupies space is called matter. CHARACTERISTICS OF MATTER : (i) Matter is composed of tiny particles called
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Integers and Absolute Values Till now we have learnt two types of number system. Those are natural numbers and whole numbers. Here we try to study whole numbers in depth Observa
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Addition of integers - As we already know addition of any two numbers a and b means moving b units to right of a on the line. The same is followed even in the addition o
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In Mathematics, fractions are defined as the parts of a whole. The whole can be an object or a group of objects. In real life, when we cut a piece of cake from the whole of it, then the portion is the
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Matter may be defined as anything that occupies space, possesses mass and presence of which can be felt by any one or more of our five senses (i.e. sight, smell, taste, touch and hearing) PHYSICAL NA
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Matter is defined as something which has some mass and occupies some space. It occurs in three different states based on physical classification. They are solids, liquids & gases. Thes
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PHYSICAL QUANTITIES: A quantity which can be measured and by which various physical happenings can be explained and expressed in form of laws is called a physica
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Dimension: Dimensions of a physical quantity are the powers to which the base quantities are raised to represent one unit of that quantity. The dimensions of a physical quantity de
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Natural Numbers : The numbers 1, 2, 3 ........... which are used in counting are called Natural numbers (or) positive integers. Whole Numbers: Natural numbers together with
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SQUARES AND SQUARE ROOTS What is special about the numbers 4, 9, 25, 64 and other such numbers? Since, 4 can be expressed as 2 × 2 = 22, 9 can be expressed as 3 × 3 = 32, all such
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Divisibility Rule of 2 If a number is even or a number whose last digit is an even number i.e. 2,4,6,8 including 0, it is always completely divisible by 2. Example: 508 is a
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Learning Objectives: Know about the properties of Rational numbers. Understand the Decimal representation of rational numbers. Understand t
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Learning Objectives : 1. Fundamental concepts 2. Fundamental operations ( Related to Algebraic expressions Real time applications: &
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Introduction Kinematics is the science of describing the motion of objects using words, diagrams,numbers, graphs, and equations. Kinematics is a branch of
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If \( \frac{x} {y} \) and \( \frac{z} {w} \) are two fractions then the fraction lying between them is \( \frac{{x + z}} {{y + w}} \) Thus we have \( \frac{x} {y},\frac{{x + z}} {
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Distance & Displacement: Distance and displacement are two quantities that may seem to mean the same thing yet have distinctly different definitions and meanings. Distance is
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When atoms of two or more elements combine, a molecule of a compound is formed. The capacities of these elements to combine with each other determine the formula of the compound formed. &
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Introduction : In order to represent the elements, instead of using full lengthy names, scientists use abbreviated names. These abbreviated names of the elements are known as
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Matter may be defined as anything that occupies space, possesses mass and presence of which can be felt by any one or more of our five senses (i.e. sight, smell, taste, touch and hearing) PHYSICAL NA
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Matter may be defined as anything that occupies space, possesses mass and presence of which can be felt by any one or more of our five senses (i.e. sight, smell, taste, touch and hearing) PHYSICAL NA
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Latent heat: The amount of heat required to change the state of matter from one state to another without rise in temperature is known as latent heat of that substance. Laten
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Introduction Kinematics is the science of describing the motion of objects using words, diagrams,numbers, graphs, and equations. Kinematics is a branch of
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Distance & Displacement: Distance and displacement are two quantities that may seem to mean the same thing yet have distinctly different definitions and meanings. Distance is
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1. Natural Numbers: The numbers generally used to count objects are calld Natural Numbers. The set of Natural Numbers is denoted by N. N = {1, 2, 3, 4, ........} Note: (i) T
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Addition of algebraic expressions (or) polynomials Addition of polynomials means adding the like terms of the polynomials Note : Unlike terms can’t be added 1.&
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Introduction : A literal symbol which can take various numerical values is called a variable (or) literal. Ex:- a, b, c, x, y, z ...........etc  
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1. History of Irrational Numbers : Hippassus (around 500BC), a Greak philosopher, is widely regarded as the first person to recognise the existence of irrational numbers. See, how he got the idea
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ABOUT ME This is my family. This is my father. This is my mother. This is my brother. He is a boy. This is my sister. She is a girl.
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HELPING OTHERS Getting back home ! Let us read Sara’s story. Sara and her family moved to a new village. Sara and her two brothers, Jacob and Samson, loved the new village. One day, Sa
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I WONDER I wonder why the grass is green, And why the wind is never seen? Who taught the birds to build a nest, And who told the trees to take a rest?” O, when the moon is not quite r
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A FAMILY ADVENTURE &nb
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Learning to Be Safe A Bus Ride Jacob, Jack and Sara go out everyday for a bus ride with their father. Let us see what happens one day when the bus was late. Jacob, Jack and Sara loved going on t
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One day, the bus was late. Father got a bar of chocolate each for Jacob, Jack and Sara. He asked them to wait while he went to buy tickets. Before going, father said, “You must never talk t
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As Jacob, Jack and Sara were sitting on the bench, a stranger came to them and said, “Hello! Do you know where the canteen is? I am thirsty and want to get something to drink, maybe a tin of jui
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THE JOY OF POPCORN Pop, pop, popcorn Popping in the pot! Pop, pop, popcorn, Eat it while it’s hot! Pop, pop, popcorn, Butter on the top! When I eat popcorn, I can&
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OUR BODY Our body is a wonderful living machine. It can see, hear, smell, taste and feel. It can also move, grow, breathe and reproduce. Our body is made up of many small parts called cells. C
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Eyes Our eyes help us to see the world around us. We see different colours, objects with our eyes. They help us to enjoy the beauty of nature and recognize things. Ears The ears help us to
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Clothes we wear Our body is very sensitive. Thus, we need to protect it from different seasons. So, to keep us warm in winter we wear woollen clothes, to keep us cool in summer, we wear cotton clot
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Leather Clothes Leather is obtained from the skin of animals like buffalo, snake, leopard, camel and crocodile. And this leather is used to make belts, jackets, shoes etc. Natural and
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NEIGHBOURHOOD INTRODUCTION All of us live in houses. There are so many houses around us where we live. Many families live in these houses. They are our neighbours. The places that are near our
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Some of these useful services are market, bus stand, school, places of worship, hospital, police station, etc. Useful Services in the Neighbourhood Market A market is a crowded and busy place wit
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Places of Worship Our neighbourhood has different places of worship. People of different religions go to different places to pray Hospital We go to a doctor at
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FOOD Introduction Our body needs food and water for several things. It needs food and water to be healthy and to make us grow. Food and water are also needed to protect us from illness. Above
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Energy Giving , Body Building , Protective Food Energy Giving Food Food items like cereals, sugar, potatoes, butter and sweets give us energy.With the help of energy, we do our daily
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Good Food Habits We should eat all types of food to keep us healthy. We should also take plenty of water to stay fit and healthy. Our body gets water from the water we drink. We also get it
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Introduction All living things need water to stay alive. We need water for many purposes like drinking, bathing, washing, cleaning, cooking and putting out fire. Plants and animals als
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Sources of Water The main source of water is the rain. The rainwater fills ponds, lakes, streams, waterfalls and rivers. Some rainwater goes deep into the ground. This i
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Drink clean Water The water that we see in ponds, lakes and rivers is not fit for drinking. It contains germs and small particles. We call it dirty water. Drinking dirty water can make us sick
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Traffic rules Hold hands while crossing the road: Hold the hands of parents, siblings or guardian while crossing the road. Say no to running: Never run across or along the road.
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Plants We see different kinds of plants around us. Some of them are big while others are small. Big plants are called trees. For example, mango, jaman, keekar, and neem etc are trees. Orang
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Parts of a Plant Roots The roots of a plant are usually underground. Roots soak up water, vitamins and minerals from the soil so that a plant has plenty of food and nutrients. 
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Flower The flower of a plant has many parts. Some flowers make fruit. Others are poisonous to eat. All flowers make pollen. The pollen is released into the wind or gets stuck on insects, an
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Flowering and non-flowering plants Some plants bear flowers and some do not bear flowers. Most of the plants grow from seeds. Seeds of one plant are different from the seeds of o
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Animals Introduction We see different kinds of animals around us. Some animals are big while some are small. Animals are living things. They breathe, eat fo
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Pet, Domestic, Wild Animals Animal Camouflage Some animals have body coverings that help them to blend in with their habitat. This is called camouflage. Different animals have differe
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Milch Animals The animals which give us milk are called milch animals. Cow, buffalo and goat are milk giving animals. Children should drink milk daily. These types of animals live in a shed
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Amphibians The animals that can live both in water and on land are called amphibians. Tortoise, frog, crocodile, etc. are amphibians. They have moist, smooth skin. Reptiles T
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Animals and their offsprings Animals’ offspring resemble their parents. They feed and take care of their offspring till they are fully grown. &n
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Numbers on abacus Abacus: a simple device for calculating, consisting of a frame with rows of wires or grooves along which beads are slid. Here is shown an abacus with 3 sticks.
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Place value and Face value The place value of a digit in a number is the value it holds to be at the place in the number. The face value of a digit in a number is numerical value of the digi
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Place value and Face value The place value of a digit in a number is the value it holds to be at the place in the number. The face value of a digit in a number is numerical value of the digi
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Expanded form and Short form In expanded form of a number, the number is shown according to the place values of its digits. This is shown here: In 180, the place values of the digits ar
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Ascending order and Descending order Ascending order When the numbers are arranged from the smallest to the largest number, those numbers are said to be in an ascending order. For example:
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Descending order When the numbers are arranged from the largest to the smallest number, those numbers are said to be in descending order. For example: Arrange the numbers in descending
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Even and Odd Numbers If we divide a number into two groups with an equal number of elements in each, then the number is an even number. In the case of odd numbers, we get a remainder of 1 whi
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Even and odd numbers on the number line What do you observe? We observe that odd and even numbers come alternately in the number series.
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Addition (+) Addition can be visualized as 'putting together' or two or more quantities. The addition is taking two or more numbers and adding them together. The sign for Addition is
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Revise: Addition of two Digit Numbers Addition by Using Expanded Form Let us add 23 and 15. So, 23 + 15 = 38
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Addition of 3-Digit Numbers Addition by Using Expanded Form Let us add 165 and 213. So, 165 + 213 = 378
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Addition without Carrying Over Let us add 321 and 456.
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Addition with Carrying Over Let us add 456 and 487
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Subtraction Subtraction is the process of taking away a number from another. It is denoted by a subtraction symbol (―). Let us understand the subtraction formula: The subtraction formul
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Subtraction of 2-Digit Numbers Subtraction by Using Expanded Form
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Subtraction of 3-Digit Numbers Subtraction by Using Expanded Form
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Subtraction without Borrowing Let us add 456 and 321.
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Subtraction with Borrowing Let us add 451 and 326.
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Multiplication Repeated Addition How many apples are there altogether? There are 3 groups. Each group has 2 apples. 2 + 2 + 2 = 6 There are 6 apples altogether. We read it as two times three
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Multiplication by table Multiplication table of 2 Multiplication table of 3 Multiplication table of 4 Multiplication table of 5 Multiplication table of 6 Multiplicati
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More about Multiplication How many keys are there in total? 2+2+2 There are 3 twos so: 2 + 2 + 2 = 3 x 2 3 x 2 = 6 There are 6 keys altogether. How many erasers are th
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Multiplication without carrying over Multiplication of a 2 digit number by a 1 digit numberExample: 21 × 3 Solution: Multiply Tens, 2 Tens × 3 = 6 TensMultiply Ones, 1 Ones &tim
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Multiplication with carrying over Multiplication of a 2 digit number by a 1 digit number Example: 23 × 4 Solution: Multiplication of a 3 digit number by a 1 digit number
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Division Repeated subtraction Rebecca had 8 balloons. Lucy took 2 balloons from her. 8 - 2 = 6 Rebecca was left with 6 balloons. Diana took 2 balloons. 6 - 2 = 4 Re
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Division Division is equal sharing or repeated subtractions. Oliver has 6 pears. He wants to put the 6 pears equally into 2 baskets. 6 divided by 2 is equal to 3. There are 3 pears
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Relationship between Division and Multiplication Rebecca has 8 balloons. She shares the balloons equally with his 4 friends. How many balloons does each friend get? 8 ÷ 4 = ?
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Division without Remainder Division of a 2-Digit Number by a 1-Digit Number Let us divide 63 by 7. • Arrange the numbers in division form. • Recall multiplication table of 7. 7
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Division with Remainder Division of a 2-Digit Number by a 1-Digit Number Let us divide 59 by 8. • Arrange the numbers in division form. • Recall multiplication table
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1.Introduction: In everyday life, we have to deal with the collections of objects of one kind or the other. For Example: i) The collection of even natural numbers less than 12 i.
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RELATIONS 1.Indtroduction : The role of relations in our daily life is very important where each relation has its own significance. For example: i) Relation of mother and son.
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Cardinal number of set: The number of distinct elements contained in a finite set is called its cardinal number and is denoted by n(A) Example: If A={1,2,3,4,5} then n(A)=5,
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1. Cartesian product (or cross product) of two sets The Cartesian product of two sets A and B, denoted by A\( \times \)B (read A cross B), is the set of all possible ordered pa
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Cardinal number of Cartesian product: The cardinal number of the Cartesian product A\( \times \)B denoted by n(AB), is the product of the cardinal numbers of the sets A and B, that is , n(A
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Cartesian product of three sets: If A, B and C are three sets, then A x B xC= {(a, b, c): a A, b B, c C} Ordered triplet is also called 3 – tuple In general if A
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Describing a relation: 1. List form or Roster form: In this method we list all the ordered pairs that satisfy the formula given in the relation. Example :- i) E is the relation having the property &
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OPERATIONS OF SETS UNION OF SETS The union of two sets A and B is the set of all those elements, which are either in A or in B ( including those which are in both) &
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VENN DIAGRAM A Venn diagram is merely a closed figure and the points of the interior of the closed figure represents the elements of the set under consideration generally given bel
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Types of relations on a set: - Suppose R is a relation on a set A. That is R\( \subseteq \)A\( \times \)A. We shall now discuss certain types of relations on a set A i) Reflexive relation: R is a r
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Inverse and Composite Functions Definition (Inverse function) : If \( f:A \to B\) is a bijection, then the relation \({f^{ - 1}} = \{ (b,a)/(a,b) \in f\}\) is a fu
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Inverse and Composite Functions Graphs of Inverse Trigonometric functions 1. Graph of \(y = {\sin ^{ - 1}}x\) 2. Graph of \( y = {\cos ^{ - 1}}x\) 3. Graph of y=tan-1
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Inverse and Composite Functions Composite functions: Let A, B, & C are three non-empty sets and let \(f:A \to B,g:B \to C\)be two functions.Since ‘f’ is a fu
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Inverse and Composite Functions Some Important properties of Inverse functions and composite functions each point is explained in detail 1. Composition of functions is not commutat
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Functions Introduction : The famous Mathematician "LEJEUNE DIRICHLET" (1805 - 1859) defined a function as follows. Let x and y are any two variables, if they are s
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Multiples And Sub-multiple Angles If A,2A, 3A ...... are called multiple angles, then \(\frac{A}{2},\,\frac{A}{3},\,\frac{A}{4}.....\) are called sub multiple angles. 1) sin
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Functions Definition of a function : Definition : Let A and B be non empty sets and 'f' be a relation from A to B if for each element \( a \in A \) , there ex
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Functions Graphical representation of function Let ‘f’ be a mapping with domain D such that y = f(x) should assume single value for each x
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Functions Typess of Functions Algebraic Functions : Functions consisting of finite number of terms of different powers of independent variable (x ) and the operations \( +
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Variation Of Graphs, Periodicity, and Extreme values Definition (periodic function, period) Let \(A \subseteq R\) and \(f:A\to R\) be a function . Then ‘f&rs
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Functions Graphs of some simple polynomial functions 1) Constant function \( f:R \to R,\,\,\,i.e\,\,\,y = f(x) = k(K \in R) \) y = K is a line parallel to x - axis 2) Identity function
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Variation Of Graphs, Periodicity, and Extreme values Variation of trigonometric Ratios 1) Variation of sinx As x increases from to 0 to \(\pi \over 2\) \(
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Variation Of Graphs, Periodicity, and Extreme values Trigonometric Fuctions and Their Graphs
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Functions One -One mapping (0r) injective (or) monomorphic : If is a function and different elements of ‘A’ have different images in B. Then ‘f’ is called one-one (or
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Variation Of Graphs, Periodicity, and Extreme values Some Important Points ¨ The period of \(\sin x,\cos x,\csc x\) and \(\sec x\) is \(2\pi\). ¨ The period of \(\tan
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General Solutions of Simple Trigonometric Equations Definition : An equation involving trigonometric functions is called a trigonometric equation Example :-\( \sin x + \cos x
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General Solutions of Simple Trigonometric Equations Principal value of an Angle (or) principal solution of an equation Definition I: There exists only one value \( \alpha \) \( \alpha \) for
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Propertics of triangle and circles connected with them Triangle : The Area of a triangle is represented by the symbol triangle for any trianlge, the three sides are represented by a, b and c &n
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Properties of triangle and circles connected with them Circum circle : The point of intersection of perpendicular bisectors of the sides of a triangle ABC is called circum center. Then SA=SB=SC=R (le
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Properties of triangle and circles connected with them Theorem : In any triangle ABC \(\frac{a}{{\sin A}} = \frac{b}{{\sin B}} = \frac{c}{{\sin C}}2R\) (sine ru
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General Solutions of Simple Trigonometric Equations Theorem :- General solution of \( \sin \theta = 0 \Rightarrow \theta = n\pi ,\,\,n \in \rlap{--} z \)\( \sin \theta = 0 \Rightarrow \theta =
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General Solutions of Simple Trigonometric Equations General Solution of some Particular equations i) \( \cos \theta = 1 \Rightarrow \theta = 2n\pi \) &
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Trigonometric Equations - 2 Theorem : General solution of \( a\cos \theta + b\sin \theta = c \) where a,b,c\(\in\)R, \( \left| c \right| \leqslant \sqrt {a^2 + b^2 } \) Pro
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MATTER: Any material which has mass and occupies space is called matter. CHARACTERISTICS OF MATTER : (i) Matter is composed of tiny particles called
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SOLIDS: Solids are one of the three main states of matter, along with liquids and gases. In a solid, particles are closely packed together in a fixed and orderly arrangement. T
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SOLIDS: Solids are one of the three main states of matter, along with liquids and gases. In a solid, particles are closely packed together in a fixed and orderly arrangement. T
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SOLIDS: Solids are one of the three main states of matter, along with liquids and gases. In a solid, particles are closely packed together in a fixed and orderly arrangement. T
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Liquids Liquids are one of the three main states of matter, alongside solids and gases. Unlike solids, which have a fixed shape, and gases, which fill the entire volume of their contain
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Gases: Gases are one of the three main states of matter, alongside solids and liquids. Gases exhibit distinct characteristics that distinguish them from the other states. Here are some key featur
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Plasma Plasma is one of the four fundamental states of matter, alongside solids, liquids, and gases. Unlike the other three states, plasma is not as commonly encountered in everyday life, as it req
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BOSE-EINSTEIN CONDENSATE: It is the fifth state of matter. Bose-Einstein condensate is a super fluid phase formed by atoms, cooled very near to abso
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PHYSICAL AND CHEMICAL CLASSIFICATION OF MATTER Matter is defined as something which has some mass and occupies some space. It occurs in three different states based on physical classification.
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Properties of different states of matter based on physical classification: The three states of matter exhibit different properties. Thei
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ELEMENTS: Substances which cannot be broken further into any other substances by any physical or chemical means are called Elements. Examples:Hydrogen,Oxygen,Nit
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ELEMENTS: Substances which cannot be broken further into any other substances by any physical or chemical means are called Elements. Examples:Hydrogen,Oxygen,Nit
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ELEMENTS: Substances which cannot be broken further into any other substances by any physical or chemical means are called Elements. Examples:Hydrogen,Oxygen,Nit
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METALS: Luster: Explanation: Metals exhibit a characteristic shiny or reflective appearance when polished. This property, known as luster, is a result of the ability of meta
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Chemical Properties: Reactivity: Metals vary in their reactivity. Some metals, like gold and platinum, are relatively unreactive, while others, like sodium and potassium, are highly reactive. Co
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NON-METALS: Non-metals are a class of elements on the periodic table that exhibit distinct physical and chemical properties from metals. Here's an explanation of some key chara
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Chemical Properties: Reactivity: Non-metals vary in their reactivity. Some non-metals, like fluorine and chlorine, are highly reactive and readily form compounds with metals. Others, like noble gas
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METALLOIDS: Metalloids, also known as semimetals, are elements that exhibit properties of both metals and non-metals. They are found along the staircase-shaped boundary on the per
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NOBLE GASES: These elements are found in air in the form of gas in very small amounts.Hence they are called as Rare gases. They are monoatomic in nature.These elements do not react
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WHAT IS A COMPOUND? A compound is like a team made up of different players (atoms). These players join together to form a new substance with its own special characteristics. In other words, a compoun
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COMPOUND DEFINITION A compounds is a pure substance made up of two or more elements chemically combined with one another in a fixed proportion by mass. It may
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CHARACTERISTICS OF A COMPOUND: We already studied that A compound is a substance composed of two or more elements that are chemically combined in fixed proportions.
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Incircle and Excircle Of a Triangle In a Circle - The internal bisectors of angles of a triangle ABC are concurrent at a point I called Incentre or the Centre of Inscribed Circle. I is
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Incircle and Excircle Of A Triangle EX - Circle : The internal bisector of an angle ‘A’ and external bisectors of an angles B and C of triangle ABC of angles are concurrent
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Properties of triangle and circles connected with them Examaples : 1. If a = 6, b =5, c = 9 then find A Solution : from the cosine rule, \(\cos A =
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Incircle And Excircle Of a Triangle Some other formulae which the relation among \( r,\,\,r_1 ,\,\,\,r_2 \,\,\& r_3 \) 1. i)\( \frac{1} {r} = \frac{1} {{r_1 }} + \frac{1} {{r_2 }}
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Quadratic Expressions-II Graph of a quadratic expression: Consider a quadratic function f(x)=ax2+bx+c, where We have f(x)=ax2+bx+c &n
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Quadratic Expressions-II Maximum and Minimum values of a Quadratic Expression: i) We have seen that when a>0, the parabola is open upward, the expression y=ax2+bx+c=0 have minim
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QUADRATIC EXPRESSIONS - I 1. Quadratic Expression: An algebraic expression of the form ax2+bx+c, where C here Cis the set of complex numbers, is called a quadratic expression in the variable
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Quadratic Expressions-II Quadratic Inequation : The inequations of the form ax2+bx+c>0, ax2+bx+cax2+bx+c<0 and ax2+bx+c \(\leqslant 0\), where are called quadratic inequations For examp
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Quadratic Expressions-II Shorttricks for calculating various forms of quadratic equation: i) If af(x) +bf(x) = a+b and ab=1 then f(x)= 1 EX: If then the value of x are
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LOCUS VARIOUS FORMS OF LINES Lous Definition: A set of points which satisfy a given condition or conditions is called a Locus Example: A Locus of points which are equidistant from a fixe
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LOCUS VARIOUS FORMS OF LINES Various Forms of a Line General form of a line: The general form of a line is ax + by + c = 0, where a, b, c are real numbers but both ‘a’ and 'b
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LOCUS VARIOUS FORMS OF LINES Slope form (or) Gradient form: The equation of the form y=mx where mR, is called slope form. This type of lines always passes through the origin. NOTE: (i) In
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LOCUS VARIOUS FORMS OF LINES Slope-Intercept form: The equation of the form y=mx+c ,where m is the slope and c is the y-intercept [i.e., The line passes through (
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Quadratic Expressions - I Relation between roots and co-efficients 7. Theorem: If \( \alpha \,\,and\,\,\beta \) are the roots of ax2+bx+c=0, then prove
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LOCUS VARIOUS FORMS OF LINES Point slope form and Two-points form Point slope form If a line passes through the point \((x_1,y_1)\) and having slope m, then equation of the line is \
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LOCUS VARIOUS FORMS OF LINES Normal form (or) Perpendicular form The equation of the line in normal form is \(x\cos \alpha + y\sin \alpha = p\) Where p = The perpendicular distance from the
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LOCUS VARIOUS FORMS OF LINES Parallel lines and perpendicular Lines The equations of two parallel lines are differ by a constant term only &
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Quadratic Expressions - I 10. Discriminant of a quadratic equation: If ax2+bx+c=0 is a quadratic equation then we know that \( x = \frac{{ - b \pm \sqrt {b^2 - 4ac} }} {{2a}} \) Her
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Foot, Image ,Distance and Angle Theorem 1: If (h,k) is the foot of the perpendicular from to the line ax+by+c=0 then \(\frac{{h - {x_1}}}{a} = \frac{{k - {y_1}}}{b} = \frac{{ - (a{x_1} +
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Quadratic Expressions - I 12. Transformed Equations :Let \( \alpha ,\beta \) be the roots of f(x) = ax2+bx+c=0, then Problem (Vii): The quadratic equation whose roots are 1 more t
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Foot, Image ,Distance and Angle Theorem II. If (h, k) is the image( (reflection) of the point \((x_1,y_1)\) w.r.t the line ax+by+c=0 , then \(\frac{{h - {x_1}}}{a} = \frac{{k - {y_1}}}{b}
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Foot, Image ,Distance and Angle Distances (1) The perpendicular distance to the line ax+by+c=0 a) from origin is \(\frac{{|c|}}{{\sqrt {{a^2} + {b^2}} }}\) b) from the point \((x_1,y_1)
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Foot, Image ,Distance and Angle Angle between two lines (i) If \(\theta\) is an acute angle between the two non- vertical lines having slopes \(m_1\) and \(m_2\) then tan\(\the
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Limits of Trignometric Functions The Function : Let A and B be two non empty sets. A function f from A to B denoted by \(f:\,A \to B\) is a rule that “assigns (or) maps every elemen
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Pair Of Straight Lines BOOST YOUR CONCEPTS 1.The point of intersection of the pair of straight lins H = ax2 + 2hxy + by2 = 0 is (0, 0). 2.If \( S \equiv ax^2 + 2hxy + by^2 + 2gx + 2fy + c
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Limits of Exponential And Logarithmic Functions 1. Exponential function : The functions of the form \( a^x ,e^x \), where x is a variable and a, e are constants are called exponential functions. e.
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Limits of Trignometric Functions Sandwich Rule : Let f and g be two real valued functions with the same domain such that for all x in the domain of definition. For some a,
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UNITS OF MEASUREMENTS OF ANGLES Measurement of Angles examples An angle can be defined as the rotation from the initial point to an endpoint of a ray. Angle measurement is the amo
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Factrorisation Of Polynomial Factorisation of Quadratic polynomial by splitting the middle term Solving a Quadratic equation \( ax^2 + bx + c = 0 \) Step I : Splitting of middle term &nb
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UNITS OF MEASUREMENTS OF ANGLES Types of Angles : Acute angles : An angle whose measure is less than \(90^0\) and greater than \(0^0\) is called an acute angle i.e., if is an ac
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UNITS OF MEASUREMENTS OF ANGLES Radian : The angle subtended from the centre of a circle which intercepts an arc equal in length to the radius of the circle. It is represented by
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Factorisation Of Polynomials Factorisation of sum and difference of cubes \( a^3 + b^3 = (a + b)(a^2 - ab + b^2 ) \) \( a^3 - b^3 = (a - b)(a^2 + ab + b^2 ) \) Ex : \( 64a^3 + 27 = (4
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Symbols And Rules ELEMENT: The substance which cannot be broken down into simpler substances by physical or chemical means is called as an Element. SYMBOL: The short hand representatio
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Symbols of elements must be written with capital letter.If two letters are present the second letter must be written in small. Examples: Element Symbol
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Mixtures The components of a mixture can easily be separated by ordinary methods.mixture is a substance containing two or more elements or compounds in any proportion.
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Types of Mixtures Mixtures are of two types: i) Homogeneous mixtures and ii)Heterogeneous mixtures i)
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SEPERATION OF MIXTURES: Mixture is said to be pure when its components are known and they are put together in a desired quantity.We need to seperate to remove unwanted substa
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i) Solvent extraction: This process is based on the property that one of the component is soluble in the solvent. Ex: A mixture
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ii) Magnetic separation: This process is based on the magnetic property of one of the component. Ex: Mixture of iron ore and sulphur. Iron ore is attracted by magnet and sulphur is
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iv) Sublimation: This process is based on the ability of one component to sublime. Ex: Mixture of iodine and sand. On heating iodine sublimes leaving behind sand.
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1. Sedimentation: The process of settling down of a heavier and insoluble components from a mixture in a liquid is called sedimentation. Ex: 1. Sedimentation o
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Evaporation: When a liquid changes into gaseous state on gentle heating, such that liquid does not boil, the process is called evaporation. The process of evaporation is employed t
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In previous chapter (Elements, Molecules and Compounds) , we have learnt about the different types of elemtns, nature of mixtures and compunds. In this chapter we shall discuss about the Symbols
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Basic concept of an atom We know that an element is a pure substance which cannot be subdivided into two or more new substance by any means. Chemists have
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BOHR-BURY SCHEME OF DISTRIBUTION OF ELECTRONS : The following rules are given by Bohr and Bury for writing the number of electrons in different energy levels or
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Atomic number: The number of protons is considered as atomic number and in case of neutral atom, electron number is also considered as atomic number. Atomic number(Z)= protons numb
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Polynomials-Types, Graphs, Factor and Remainder Theorem Indtroduction : Algebra is the branch of mathematics which explain the relation among the constants and variables. Constants and variable
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Polynomials-Types, Graphs, Factor and Remainder Theorem 6) Definition of polynomial : A polynomial is an algebraic expression in which each variable involved has power (ex
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Polynomials-Types, Graphs, Factor and Remainder Theorem 8) Zeroes of a polynomial : If for x = K the value of a polynomial p(x) is ‘0’ i.e p(k) = 0 called zero of the polynomial a) A
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TRIGONOMETRIC RATIOS Introduction: The word ‘ trigonometry’ is derived from the Greek roots .. ‘tri’ means ‘three’ ; ‘gonia’ means
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TRIGONOMETRIC RATIOS Pythogoras Theorem : In a right-angled triangle, the sum of the squares of the two sides (other than hypotenuse) of a right-angled triangle is equal to the sq
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TRIGONOMETRIC RATIOS Behaviour of trigonometric functions sin\(\theta\), cos\(\theta\) and tan\(\theta\) as \(\theta\) changes from 00 to 900. i.e., \({0^0} \leqslant \theta \leqslant {90^
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TRIGONOMETRIC RATIOS Trigonometric function of complementary angles 1. Consider a right angled triangle ABC, right angled at B. Let \(\angle A = \theta \) then \(\angle C = \left( {90 - \theta
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TRIGONOMETRIC IDENTITIES Prove that I) \({\sin ^2}\theta + {\cos ^2}\theta = 1\) II)\(1 + {\tan ^2}\theta = {\sec ^2}\theta \) III)\(1 + {\cot ^2}\theta =
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Elimination of angle Elimination of angle (\(\theta\)) by using trigonometric identities The process of transforming trigonometric equation into an Algebric equation using trigonome
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HEIGHTS AND DISTANCE Line of sight : Let \(\overleftrightarrow {OX}\) be a horizontal line an ‘p’ be the position of object above (or) below the horizontal line, then the line
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ANGLES IN QUADRANTS Introduction : (1) Trigonomentry = tri + gono + metron \(\Rightarrow \) Tri = three, gono = Angles, metron = measurement &n
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ANGLES IN QUADRANTS Angle : The amount of Rotation of moving ray with reference to fixed ray is called an Angle. Generally angles are represented by \(\theta ,\alpha ,\beta .......\)
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ANGLES IN QUADRANTS Behaviour of trigonometric Ratios \(\sin \theta ,\cos \theta ,\tan \theta \) as ‘\(\theta\) ‘ changes from o0 to 900 i.e., .\(0 \leqslant \theta \leqslant
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ANGLES IN QUADRANTS If \(\theta=90^0\) Let \(op = r = 1{U}\) op will coincide with Y-axis \(\therefore \,\,op = y = 1 = r\) x = 0
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ANGLES IN QUADRANTS If \(\theta=\) 300 and 600 The values of trigonometric ratios are defined from equilateral triangle, Let \(\Delta ABC\) be an equilateral tria
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ANGLES IN QUADRANTS The values of trigonometric ratios of 1800 If =1800, then op coincide ‘with ox’ Let op = r = 1 x = -1, y = 0
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ANGLES IN QUADRANTS The value of Trigonometric ratios of \((-\theta)\) Let be the right angled triangle
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ANGLES IN QUADRANTS Trigonometric function of complementary Angles Consider a right angled triangle ABC, right angled at B Let \(\angle A=\theta\) \(\therefore \angl
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ANGLES IN QUADRANTS Sign of Trigonometric ratios (by using ALL silver TEA cups) 1. If ' \(\theta\)' lies in Q1, Q2, Q3 and Q4 then the sign of trigonometric ratios are as f
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Arithematic Progressions Upto nth term 1. Sequence : In mathematics a sequence is an ordered list of objects (or events or numbers) Note: &nb
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Arithematic Progressions Upto nth term Progression: It is not necessary that the terms of a sequence always follow a cercation pattern or they are described by some explicit
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Arithematic Progressions Upto nth term Solved Problems Problem1 : If \(a,b,c \in {R^ + }\) form an A.P, then prove that \(a + \frac{1}{{bc}},\,b + \frac{1}{{ac}},\,c + \frac{1}{{ab}}\) are
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Sum of n terms of an Arithmetic Progression 1.Theorem : Let a be the first term, d be the common difference, n be the number of terms and sn be the sum of first n terms of an Arithmetic progression ,
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Polynomials-Types, Graphs, Factor and Remainder theorem Types of polynomials : i) Constant polynomial : A polynomial having degree ‘0’ is called constant polynomial &n
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Polynomials-types, Graphs, Factor And Remainder Theorem 12. Remainder Theorem Let p(x) be a polynomial of degree greater than or equal to one, if p(x) is divided by (x - a). Then
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Polynomials-Types, Graphs, factor and Remainder theorem Some Algebraic Identities 1.\( (a + b)^2 = a^2 + 2ab + b^2 \) 2.\( (a - b)^2 = a^2 - 2ab + b^2 \) 3.\( (a + b)^2 + (a - b)^2
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Polynomials-Types, Graphs, Factor and Remainder theorem Factor Theorem : Let p(x) be a polynomial of any degree if , then (x-k) is said to be factor of p(x) ex : Let \( p(x) = x^2 - 5x + 6 \)&n
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Polynomials-Types, Graphs, Factor and Remainder theorem Synthetic division of Horner’s method Horner’S Method of synthetic deivision : We shall explain the method with the following e
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Polynomials-types, Graphs, Factor and Remainder theorem H.C.F and L.C.M of Polynomials : If a polynomial p(x) is a product of two polynomials h(x) and g(x)i.e., \( f(x) = g(x) \times h(x) \)&nb
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Geometric Progressions 1. Geometric progression: A sequence is called a geometric progression (G.P) if the ratio of any two consecutive terms is the same. Examples:i)\( 1,\frac{1} {2},\frac{1} {4}
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Geometric Progressions Problem 1 : Find the geometric mean between -9 and -16. Solution : Required G.M \( = \sqrt {\left( { - 9} \right) \times \left( { - 16} \right)} \) &
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Cartesian Plane Introduction Mathematics in ancient days was divided into two branches ‘Algebra’ and ‘Geometry’. Algebraic equations
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Cartesian Plane Quadrants : The X-axis and the Y-axis divides the plane in four independent regions called as 'Quadrants'. 4. The coordinates of various points in the q
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Coordinate Geometry - Distance between Two Points 1. The distance between two points which lie on the X-axis: The distance between the points A (x1,0) and B (x2, 0) is AB = |x1-x2| 2. The distan
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Coordinate Geometry-Distance between two points 7. Types of Quadrilaterals The quadrilateral formed by A(x1, y1), B(x2, y2), C(x3, y3) and D(x4, y4) is
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Coordinate Geometry-Section , Area Of Triangle 1.Internal division : Let A and B be the end points of a line segment . If a point P(other than A and B) lies on the line segment \(\overline {AB}
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Coordinate Geometry-Section , Area Of Triangle Theorem 1 : If a point P(x, y) divides the line segment joining the points A(x1,y1) and B(x2,y2) in the ratio m : n then \(P\left( {x,y} \right) =
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Coordinate Geometry-Section , Area Of Triangle Mid Point of a Line Segment :
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Coordinate Geometry-Section , Area Of Triangle Theorem 2: If a point P(x, y) divides the line segment joining A(x1,y1) and B(x2,y2) in the ratio m : n externally, then\(P\left( {x,y} \rig
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Coordinate Geometry-Section , Area Of Triangle Coordinates of different centres of a triangle : Centroid of a triangle: The point of concurrency of the medians of a triangle is called the centroid
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Coordinate Geometry-Section , Area Of Triangle Area of a triangle : Theorem : If \(A\left( {{x_1},{y_1}} \right),B\left( {{x_2},{y_2}} \right)\)and \(C\left( {{x_3},{y_3}} \right)\) are t
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GEOMETRY- LINES AND ANGLES Basic Geometrical Concepts Point: A fine dot marked with a sharp edged pencil represents a point. It has no length, breadth and thickness. Points are denoted by capital le
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GEOMETRY- LINES AND ANGLES Basic Geometrical Concepts Plane: In mathematics, a smooth flat surface which extends endlessly in all the directions is called a “Plane” Example: 1. Surface
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GEOMETRY- LINES AND ANGLES LlNE SEGMENT: A part of a line with two end points is called a line segment. A line segment whose end points are A and B is denoted by . i. e it has only le
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GEOMETRY- LINES AND ANGLES Lines and Angles Angle: An angle is the union of two different rays having the same initial point (or) Amount of rotation. The common point i
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GEOMETRY- LINES AND ANGLES Types of angles: Acute angles:An angle whose measure is less than 90° and greater than O° is called an acute angle i.e., If \(\theta \) is an acute angle, th
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GEOMETRY- LINES AND ANGLES Different Points And Lines Coplanar points: Points are coplanar if and only if they lie in the same plane.The points which are not on the same pl
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COMPOUND ANGLES 1) If \(A,B,C,\alpha ,\beta ,\gamma .....\)are any angles then \(A + B + C + A + B - C,A - B + C,\) are called compound Angles. Theorem : For all&
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COMPOUND ANGLES Theorem 2 : If none of the angles A, B, A+B, and A-B are an odd multiples of \(\frac{\pi }{2}\) i)\(\tan (A + B) = \frac{{\sin (A + B)}}{{\cos (A + B)}}\) \(= \frac{{\sin A\cos
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COMPOUND ANGLES Theorem 3 : If none of the angles A, B, A + B, A - B are an Integral multiple of \(\pi\), then i) \(\cot (A + B) = \frac{{\cot A.\cot B - 1}}{{\cot B + \cot A}}\)&nb
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COMPOUND ANGLES Theorem 4: Prove that : 1)sin(A+B) . sin(A-B) =sin2A -sin2B (or) cos2B - cos2A 2)cos(A+B).cos(A-B) =cos2A -sin2B (or) cos2B - sin2A 3)\(\tan (A + B).\tan (A - B) = \frac{{{{\
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COMPOUND ANGLES Theorem 5 : Prove that for any three non-zero Angles A, B, C i)\(\sin (A + B + C) = \sin A.\cos B.\cos C + \cos A.\sin B.\cos C\) \(+ \cos A.\cos B.\sin C - \sin A.
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Geometry-Polygons 1.Curve (definition) : A plane figure formed by joining a number of points without lifting a pencil from the paper and without retracing any position of the drawing o
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Geometry-Polygons 5. Polygons: a polygon is a closed curve formed by the line segments such that (i) no two line segments intersect except at their end points (ii) no two line segments with
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Trivalent Electronegaive ions: A Radical or Ion which is formed by gaining of three electrons is called Trivalent Electronegaive ions. Tetravalent negative ions: &
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Geometry-Polygons 13.The interior angle sum property: The sum of the angles of a quadrilateral is or 4 right angles. \( \left| \!{\underline {\, A \,}} \right. + \left| \!{\underline
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Geometry-Polygons 15. Varions types of Quadrilaterals (i)Trapezium (ii) Isosceles Trapez
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What is atom made up of ? An atom consists of two parts : (a) Nucleus : Nucleus is situated in the centre of an atom. All the protons &
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Multiples And Sub-Multiples If A,2A, 3A ...... are called multiple angles, then \( \frac{A} {2},\,\frac{A} {3},\,\frac{A} {4}..... \) are called sub multople angles. 1) sin 2A = 2 sinA cosA
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Multiples and Sub multiples Proof : We know, i) sin (A + B) = sinA . cosB + cosA . sinB Put A = B sin 2A = sinA cosA + cosA . sinA ii) cos (A + B
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Multiples And Sub-Multiples We know, \( \sin 3A = \sin (2A + A) = \sin 2A.\,\cos A + \cos 2A\,\,.\sin A \) &nbs
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Multiples And Sub-Multiples We know sin2A = 2 sinA cosA put A =\( \frac{A} {2} \) &n
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Multiples And Sub-Multiples We know sin3A=3 sinA - 4 sin3A Put A =\( \frac{A} {3} \) sinA = 3sin\( \frac{A} {3} \) - 4sin3\
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Multiples And Sub-Multiples Theorem : When cos2A is known, then the value of sinA, cosA tan A and cotA in terms of cos2A i) \( \sin A = \pm \sqrt {\frac{{1 - \cos 2A}} {2}} \)
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Multiples And Sub-Multiples Theorem : Prove that i)\( \sin 18^0 = \frac{{\sqrt 5 - 1}} {4} \) ii)\( \cos 18^0 = \frac{{\sqrt {10 + 2\sqrt 5 } }} {4} \) &
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Multiples And Sub-Multiples Theorem : Prove that i)\( \sin 22\frac{1} {2}^0 = \sqrt {\frac{{\sqrt 2 - 1}} {{2\sqrt 2 }}} \) ii)\( \cos 22\frac{1} {
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Multiples And Sub-Multiples Theorem Prove that:i)\( \sin 7\frac{1} {2}^0 = \frac{{\sqrt {4 - \sqrt 6 - \sqrt 2 } }} {{2\sqrt 2 }} \) ii)\( \cos 7\frac{1} {2}^0 = \frac{{\sqrt {4 + \s
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Multiples And Sub-Multiples Theorem Prove that:i)\( \sin 7\frac{1} {2}^0 = \frac{{\sqrt {4 - \sqrt 6 - \sqrt 2 } }} {{2\sqrt 2 }} \) ii)\( \cos 7\frac{1} {2}^0 = \frac{{\sqrt {4 + \s
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Multiples And Sub-Multiples Transformation : Theorem : for all C,D\( \in \) R 1) sinC + sinD =\( 2sin\frac{{C + D}} {2}.\cos \frac{{C - D}} {2} \) 2) sinC - sinD = \( 2sin\frac{{C
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Congruence, Inequality On Sides of Triangles “Congruence” concept is used to classify geometrical figures on the basis of their shapes. WHAT IS CONGRUENCE? In geo
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Congruence, Inequatlity on Sides Of Triangles Congruence in Circles: In the context of circles, congruence refers to the equality of two circles in terms of their radii. Two cir
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When atoms of two or more elements combine, a molecule of a compound is formed. The capacities of these elements to combine with each other determine the formula of the compound formed. &
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Modern Definition of Valency : According to the new concepts, Valency can be defind as the number of electrons that are lost or gained or shared with one atom of
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Congruence, Inequality On Sides Of Triangles Side-Angle-Side(SAS) congruence criterion: The Side-Angle-Side (SAS) congruence criterion is one of the methods used in geome
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EARNING OBJECTIVES: Introduction Classification of changes Slow and fast changes
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Desirable and undesirable changes §§ Desirable change: A change brought about by a person (or) the nature, which is useful, is called a desirable chan
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§§ Periodic and non periodic changes: Periodic Changes: The changes which occur again and again, after fixed intervals of time, are called periodic changes.
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Physical and chemical changes: All substances around us undergo changes. In some cases, the changes are small and difficult to defect. In other cases, the change
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What are Chemical Changes? A chemical change is one where there are changes in the chemical properties of the components. Their chemical composition may change and the final product may have differen
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Factorials 1. Factorial Notation : The product of first n natural numbers is denoted by and is read as “factorial n”.This \( n! = 1 \times 2 \time
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CYCLICITY AND CONGRUENCE MODULO CYCLICITY 1. This concept is mainly about the unit digit of a number and its repetitive pattern on being divided by a certain number 2. The concept of cyclicit
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Factorials 1. Factorial Notation : The product of first n natural numbers is denoted by and is read as “factorial n”.This \( n! = 1 \times 2 \times
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CYCLICITY AND CONGRUENCE MODULO CONGRUENCE OF NUMBERS 1. Two integers a and b are said to be congruent modulo m, if a and b have the same remainder when they are divided by a non zero integer m. Th
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Factorials 5. Some Illustration Examples : Examples: (i) Find n, if \( \left( {n + 1} \right)! = 12 \times \left( {n - 1} \right)n \) Solution:\( \left( {n + 1} \right)! = 12 \
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Factorials Number of trailing zeros in n! : Number of trailing zeros in n! = no. of times n! is divided by 10  
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Geometry-Lines And Angles Parallel lines: Two lines ‘l’ and ‘m’ are said to be parallel, if they lie in the same plane and do not have a common poi
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Factorials NOTATION : Let n and r be two positive integers such that \(r\le n\) then he value of \(\frac{{n!}}{{\left( {n - r} \right)!}}\) is denoted by \({}^n{p_r}\) i.
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TYPES OF NUMBERS Numerals : Any figure or symbol that is used to indicate a number is a numeral. Digits: Any arabic numeral (0-9) is a digit. Digits are used to form natural numbers and whole number
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PRIME AND COMPOSITE NUMBERS 1. Observe the number of factors of some numbers arranged in the following table We can see that i) The number ‘1’ has
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PRIME AND COMPOSITE NUMBERS SIEVE OF ERATOSTHENES:- Step -I Cross out ‘1’ because it is not a prime number Step - II Encircle 2, cross out all the multiples of 2, ot
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PRIME AND COMPOSITE NUMBERS EVEN NUMBERS:- All numbers divisible by ‘2’ are called even numbers 2, 4, 6, 8 ...... ODD NUMBERS:-
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RATIONAL NUMBERS, PROPERTIES, OPERATIONS Natural Numbers : The numbers 1, 2, 3 ........... which are used in counting are called Natural numbers (or) positive integers. Whole Num
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RATIONAL NUMBERS, PROPERTIES, OPERATIONS Properties of Rational number Rational numbers are numbers that can be expressed as the quotient or fraction of two integers, where the numerator is an
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RATIONAL NUMBERS, PROPERTIES, OPERATIONS Additional Properties of Rational Numbers 1) Law of Tricotomy: For every a,b,\(\in\) Q any one of the following is hold. i) a<b
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Rational Numbers, Properties, Operations How to find the rational numbers between two rational numbers? There are infinite numbers of rational numbers betwe
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Rational Numbers, Properties, Operations Rational Numbers in Ascending Order We will learn how to arrange the rational numbers in ascending order. General method to arrange from smallest to lar
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Rational Numbers, Properties, Operations Operations on rational numbers Addition : There are two possibilities 1. Rational numbers with same denominator 2. Rational numbers with different denomi
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Rational Numbers, Properties, Operations Multiplication of rational numbers Product of two rational numbers is equal to the product of numerators divided by the product of denominators. i.e.,&nbs
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Rational Numbers, Properties, Operations Simplification: Rational numbers can often be simplified by dividing both the numerator and denominator by their greatest common factor. For example: 4/8
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Decimal Representation Of Rational Numbers We can get the decimal representation of the rational number \( \frac{p} {q} \) by long division method. When we divide
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Decimal Representation Of Rational Numbers Conversion of decimal numbers into rational numbers of the form Case-1 : When decimal number is of terminating nature. step 1 : Write the given de
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Decimal Representation Of Rational Numbers In order to convert a rational number to a decimal, we divide the numerator with the denominator. Sign will be the same as the equivalent decimal.
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Square And Square Roots, Cube and Cube Roots Types of numbers : i) Natural numbers : Conting numbers 1,2,3,4... are called natural numbers. Natural numbers are denoted by the letter N.
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Square And Square Roots, Cube And Cube Roots Main Points Related to Squares, Square roots and cube, cube roots 1. A number is multiplied by it self the product so obtained is called th
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Square And Square Roots, Cubes And Cube Roots Methods for finding square roots 1. Method of successtive subraction we subtract the numbers 1,3,5,7..... successively till we
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Sqaure And Square Roots, Cube And Cube Roots Cube roots 9. If ‘n’ is perfect cube then for some integer ‘n’. n = m3, then the number m is called the cube root of &lsqu
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Fundamentals Of Surds Let 'a' be a positive rational number and 'n' be a positive Integer \( \left( { \ne 1} \right) \) if \( \sqrt[n]{a} \) or \( a^{\frac{1} {n}} \)
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Fundamentals Of Surds Laws of radicals : 1. If \( \sqrt[n]{a} \) and \( \sqrt[n]{b} \) are two radicals of same order, then \( \sqrt[n]{a} \) x\( \sqr
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Operations On surds Operation on Surds Addition and Multiplication of Surds : Two Surds can be added or subtracted from the other by using distribution law, only when they are
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RATIONALISATION OF SURDS Rationalising factor:- If the product of two surds is a rational number, then each of them is called a rationalising factor of each other Note: 1)
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RATIONALISATION OF SURDS Rationalisation of monomial surds:- * If \(n\sqrt{a}\) is the simplest form of a surd then its R.F is \(\sqrt[n]{{{a^{n - 1}}}}\) Example:- Simplest fo
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RATIONALISATION OF SURDS Rationalising factors of Binomial surds 1) R.F of \(\sqrt a + \sqrt b = \sqrt a - \sqrt b \) and R.F of \(\sqrt a - \sqrt b = \s
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RATIONALISATION OF SURDS Rationalation of Trinomial surds 1) \(\left( {{x^{\frac{1}{3}}} + {y^{\frac{1}{3}}} + {z^{\frac{1}{3}}}} \right)\left( {{x^{\frac{2}{3}}} + {y^{\frac{2}{3}}} + {y^{\fr
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RATIONALISATION OF SURDS Conjugate surds:- The binomial surds of the form \(a + \sqrt b ,a - \sqrt b ,\) are called conjugate surds. Here, each surd is called the conjugate of the other.
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DIVISIBILITY RULES STORY OF DIVISIBILTY RULE Once upon a time in the kingdom of Mathematics, there were four siblings named Divis, Ibility, Rulina, and Esquire. Eac
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DIVISIBILITY RULES Divisibility Rule of 2 If a number is even or a number whose last digit is an even number i.e. 2,4,6,8 including 0, it is always completely divisible by 2
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DIVISIBILITY RULES Divisibility Rule of 5 Numbers, which last with digits, 0 or 5 are always divisible by 5 Example: 10, 10000, 10000005, 595, 396524850, etc Properties Of Divis
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DIVISIBILITY RULES Divisibility Rule of 8 If the number formed by last three digits of a number are divisible by 8, then the number is completely divisible by 8 Example: Ta
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DIVISIBILITY RULES Divisibility Rules for 11. If the difference of the sum of alternate digits of a number is divisible by 11, then that number is divisible by 11 completely
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LCM AND HCF Prime factorisation : When a number is expressed as a product of prime numbers,we call it as the prime factorisation of that number. (O
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LCM AND HCF H.C.F by using factors To find the Highest Common Factor (HCF) of two or more numbers using their factors, you can follow these steps List the factors: Identify all the factors of each
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LCM AND HCF H.C.F by using prime factorisation Finding the Highest Common Factor (HCF) using prime factorization involves expressing each number as a product of its prime factors and then identifyin
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LCM AND HCF Division Method We find the H.C.F two given numbers using the steps given below Step I : Divide the larger number by the smaller number. Step II : Divide the divisor by the
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LCM AND HCF LEAST COMMON MULTIPLE Definition : The least common multiple of two or more numbers is the least natural number that is a multiple of the given numbers. L.C.M can be determined by three
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LCM and HCF L.C.M by Prime Factorisation Method: To find the Least Common Multiple (LCM) of two or more numbers using the prime factorization method, you can follow these steps:
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LCM and HCF L.C.M by synthetic division method In order to find the L.C.M of two or more numbers by division method the steps given below are followed. 1) Write
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LCM and HCF HCF and LCM of fractions : HCF of given fractions = \(\frac{{HCF\,\,of\,\,numerators}}{{LCM\,\,of\,\,deno\min ators}}\) Ex : HCF of 
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EXPONENTS AND POWERS STORY OF EXPONENETS AND POWERS Once upon a time in the kingdom of Mathlandia, there lived a young mathematician named Alex. Alex was known for their cur
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EXPONENTS AND POWERS Exponent : For any rational number 'a' and natural number 'n' multiplication of 'a' n times symbolically written as (read as a to the power of n)
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Exponents And Powers Some other formulas \( i)\sqrt[n]{{\frac{x} {y}}} = \frac{{\sqrt[n]{x}}} {{\sqrt[n]{y}}} = \frac{{x^{yn} }} {{y^{yn} }} \)
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EXPONENTS AND POWERS Terms of Exponents (or) laws of Indices Multiplication Property: The law of exponents for multiplication states that when you multiply two expone
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EXPONENTS AND POWERS Division Property : The division property of exponents states that when you have a quotient of two exponential expressions with the same base, you can s
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EXPONENTS AND POWERS Power of a power property: The power of a power property of exponents states that when you have an exponential expression raised to another exponent, yo
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Exponents And Powers Power with exponent zero law : The power with an exponent zero law of exponents states that any non-zero number raised to the power of zero is equal to 1. M
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Exponents And Powers Quotient of Powers with the Same Exponent: \( \left( {\frac{x} {y}} \right)^m = \frac{{x^m }} {{y^m }} \) When you divide two numbers each raised to the same exponent, y
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Exponents And Powers Product of Powers with the Same Exponent: \( \left( {xy} \right)^m = x^m \times y^m \) When you multiply two num
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Fundamentals Of Logarithms Introduction : We know 20 = 1, 21 = 2, 22 =4, etc 1) If 2x = 15, exactly we can’t say x value but by using logarithms, we can find the va
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Fundamentals Of Logarithms Types of logarithms : There are two types of logarithms which are general used Common logarithms: The logarithms which are calculate to the base ‘10&rs
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Factorials Factorials have been discovered in several ancient cultures, notably in Indian mathematics the canonical works of Jain literature, and by Jewish mystics in the Talmudic book Sefer Yetzir
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Formulae, Characteristic And Mantissa Introduction : We know 20 = 1, 21 = 2, 22 =4, etc 1) If 2x = 15, exactly we can’t say x value but by using logarithms, we can
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Formulae, Characteristic, Mantissa Types of logarithms : There are two types of logarithms which are general used Common logarithms: The logarithms which are calculate to the base &lsq
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Formulae, Characteristic And Mantissa Characterstic and mantissa Observation :- \( 10^0 = 1 \Rightarrow \log _{10}^1 = 0 \) \( 10^1 = 10 \Rightarrow \log _{10}^{10} = 1
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CYCLICITY This concept is mainly about the unit digit of a number and its repetitive pattern on being divided by a certain number. The concept of cyclicity can be learned by fighring out the u
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CYCLICITY Digits 4 & 9 : Both these numbers have a cyclicity of only two different digits as their unit’s digit. 41=4 42=16 43=64 and so on. &nbs
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CYCLICITY Digits 2, 3, 7 & 8 : These numbers have a power cycle of 4 different numbers. \({2^1} = 2,{2^2} = 4,{2^3} = 8\& {2^4} = 16\) and after that it starts repea
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ADDITION & SUBTRACTION OF ALGEBRAIC EXPRESSION OR POLYNOMIALS STORY ON ADDITION AND SUBTRACTION OF ALGEBRAIC EXPRESSION Once upon a time in the small town of Mathlandia, there were two rival g
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ADDITION & SUBTRACTION OF ALGEBRAIC EXPRESSION OR POLYNOMIALS ADDITION OF ALGEBRAIC EXPRESSIONS Addition of algebraic expressions involves combining like terms and simplifying the resulting expr
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ADDITION & SUBTRACTION OF ALGEBRAIC EXPRESSION OR POLYNOMIALS RULES FOR COMBINING UNLIKE TERMS When adding algebraic expressions with unlike terms, you still follow some basic rules, but in this
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ADDITION & SUBTRACTION OF ALGEBRAIC EXPRESSION OR POLYNOMIALS SUBTRACTION OF ALGEBRAIC EXPRESSIONS Subtraction of algebraic expressions involves combining like terms and simplifying the expressi
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ADDITION & SUBTRACTION OF ALGEBRAIC EXPRESSION OR POLYNOMIALS Horizontal method : Rule: The expression to be subtracted is first enclosed in brackets with a minus sign prefixed, then on removal
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MULTIPLICATION & DIVISION OF ALGEBRAIC EXPRESSION OR POLYNOMIALS Once upon a time in the land of Mathematics, there were two brave warriors named Monomi and Binomi. Monomi was a solitary figure,
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MULTIPLICATION & DIVISION OF ALGEBRAIC EXPRESSION OR POLYNOMIALS MULTIPLICATION OF ALGEBRAIC EXPRESSIONS Multiplication of algebraic expressions involves the following steps.  
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MULTIPLICATION & DIVISION OF ALGEBRAIC EXPRESSION OR POLYNOMIALS division of an algebraic expression What is Division of Algebraic Expressions ? In the division of an a
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Fundamentals of Polynomials Polynomial Definition Polynomials are expressions with one or more terms with a non-zero coefficient. A polynomial can have more than one term. An algebraic expression p(
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Fundamentals of Polynomials Types of polynomials depending upon degree : 1. Constant polynomial: A polynomial with ‘0’ as degree is known as constant polynomial.
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Fundamentals of Polynomials Types of Polynomials depending on number of terms Depending upon the number of terms, polynomials are divided into the following categories: Monomial  
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Fundamentals of Polynomials *Equation : A statement of equality involving one or more variables is called an equation (or) An equation is a statement in which two algebraic
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Fundamentals of Polynomials Transposition : Any term of an equation may be taken to the other side with its sign changed,without affecting the equality.This process
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LINES AND ANGLES Point: A fine dot marked with a sharp edged pencil represents a point. It has no length, breadth and thickness. Points are denoted by capital letters like A,B,C etc., Geometrically a
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LINES AND ANGLES Plane: In mathematics, a smooth flat surface which extends endlessly in all the directions is called a “Plane” Example: 1. Surface of a black board in your class room.&n
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LINES AND ANGLES Line Segment LlNE SEGMENT: A part of a line with two end points is called a line segment. A line segment whose end points are A and B is denoted by \(\overline {AB} \,\,or\,\,\
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LINES AND ANGLES Angle: An angle is the union of two different rays having the same initial point (or) Amount of rotation. The common point is called the vertex. The siz
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LINES AND ANGLES Types of angles: Acute angles:An angle whose measure is less than 90° and greater than O° is called an acute angle i.e., If is an acute angle, then Right
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LINES AND ANGLES Operations with angles: Consider \(\angle{AOB}\) and \(\angle{BOC}\) in the above figure. Both \(\angle{AOB}\) and \(\angle{BOC}\) have a common
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LINES AND ANGLES Pairs of angles: i) Adjacent angles: Two angles in a plane are called adjacent angles, if they have a common vertex, a common side and t
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LINES AND ANGLES Parallel lines: Two lines ‘l’ and ‘m’ are said to be parallel, if they lie in the same plane and do not have a common point.
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LINES AND ANGLES Coplanar points: Points are coplanar if and only if they lie in the same plane.The points which are not on the same plane are called non coplanar poin
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LINES AND ANGLES Transversal: A straight line that intersects two or more lines is called a transversal. &
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LINES AND ANGLES Intercept and ITs Properties Intercept: Consider any two lines l and m and a transversal n intersect l and m at A and B respectively. Th
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UNITS OF MEASUREMENTS OF ANGLES Measurement of Angles examples An angle can be defined as the rotation from the initial point to an endpoint of a ray. Angle measurement is the amo
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UNITS OF MEASUREMENTS OF ANGLES i) Sexagesimal system or British system : The Sexagesimal system is the most prevalent system of measurement where a right angle is divided into 90 equal parts called
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MULTIPLES AND FACTORS Recap of Types Of Numbers Natural numbers : The counting numbers are known as natural numbers. &nbs
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MULTIPLES AND FACTORS What are factors? Factors are the numbers that can divide a number exactly. Hence, after division, there is no remainder left. Factors are the numbers you multiply togeth
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MULTIPLES AND FACTORS Factor trees : The diagrams given here, are called as “factor trees”. The factors of a number. A factor divides its mutliple
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MULTIPLES AND FACTORS Difference Between Factors and Multiples The difference between factors and multiples are given here in tabular form. Go through the below table to understan
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PRIME AND COMPOSITE NUMBERS 1. Observe the number of factors of some numbers arranged in the following table We can see that i) The number ‘1’ has
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PRIME AND COMPOSITE NUMBERS SIEVE OF ERATOSTHENES:- Step -I Cross out ‘1’ because it is not a prime number Step - II Encircle 2, cross out all the multiples of 2, other th
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PRIME AND COMPOSITE NUMBERS EVEN NUMBERS:- All numbers divisible by ‘2’ are called even numbers 2, 4, 6, 8 ...... ODD NUMBERS:- Number
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DIVISIBILITY RULES STORY OF DIVISIBILTY RULE Once upon a time in the kingdom of Mathematics, there were four siblings named Divis, Ibility, Rulina, and Esquire. Eac
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DIVISIBILITY RULES 1.Divisibility by 2:- A natural number is divisible by ‘2’ if and only if the digit in its units place i
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DIVISIBILITY RULES Divisibility by ‘6’ :- A natural number is divisible by 6, if it is divisible by 2 and 3 . eg:- 30702 unit place contains ‘2’ then it i
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Divisibility by ‘9’: - A natural number is divisible by ‘9’, if and only if sum of the digit is divisible by ‘9’. eg:- 1) 306019 = 2 + 0 + 6 + 0 + 1 + 9 = 18 is di
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LCM AND HCF Prime factorisation : When a number is expressed as a product of prime numbers,we call it as the prime factorisation of that number. (O
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LCM AND HCF H.C.F by using factors To find the Highest Common Factor (HCF) of two or more numbers using their factors, you can follow these steps List the factors: Identify all the factors of each
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LCM AND HCF H.C.F by using prime factorisation Finding the Highest Common Factor (HCF) using prime factorization involves expressing each number as a product of its prime factors and then identifyin
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LCM AND HCF Division Method We find the H.C.F two given numbers using the steps given below Step I : Divide the larger number by the smaller number. Step II : Divide the divisor by the
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LCM AND HCF LEAST COMMON MULTIPLE Definition : The least common multiple of two or more numbers is the least natural number that is a multiple of the given numbers. L.C.M can be determined by three
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LCM and HCF L.C.M by Prime Factorisation Method: To find the Least Common Multiple (LCM) of two or more numbers using the prime factorization method, you can follow these steps:
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LCM and HCF L.C.M by Prime Factorisation Method: To find the Least Common Multiple (LCM) of two or more numbers using the prime factorization method, you can follow these steps:
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LCM and HCF L.C.M by synthetic division method In order to find the L.C.M of two or more numbers by division method the steps given below are followed. 1) Write
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INTEGERS AND ABSOLUTE VALUES Integers and Absolute values Till now we have learnt two types of number system. Those are natural numbers and whole numbers. Here we try to stu
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INTEGERS AND ABSOLUTE VALUES Types of Integers: 1. Positive Integers (Natural Numbers): Definition: Positive integers are whole numbers greater than zero. Sym
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INTEGERS AND ABSOLUTE VALUES IMPORTANT INFORMATION ABOUT INTEGERS Odd and Even Patterns: All integers can be classified as either odd or even. Odd integers ca
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INTEGERS AND ABSOLUTE VALUES Number line : The integers are represented by points at equal intervals on a line is called number line. Representation of Integers on number l
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INTEGERS AND ABSOLUTE VALUES Absolute value of an integer : The absolute value of an integer is the numerical value of the integer irrespective of its sign the symbol &lsquo
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INTEGERS ARTHIMETIC OPERATIONS AND ABSOLUTE VALUES STORY ON PROPERTIES OF INTEGER Once upon a time in the quaint town of Numerica, there lived four friends named Addy, Subby, Multi, and D
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INTEGERS ARTHIMETIC OPERATIONS AND ABSOLUTE VALUES Addition of integers As we already know addition of any two numbers a and b means moving b units to right of a
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TRIGONOMETRIC RATIOS Introduction: The word ‘ trigonometry’ is derived from the Greek roots .. ‘tri’ means ‘three’ ; ‘gonia’ means
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TRIGONOMETRIC RATIOS Definition of Sin\(\theta\)\(\theta\) , cos \(\theta\) \(\theta\) , tan\(\theta\) \(\theta\)and their reciprocals ( for \(0 < \theta < \frac{\pi }{2}\)\(0 &l
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TRIGONOMETRIC RATIOS Behaviour of trigonometric functions sin \(\theta\), cos\(\theta\) and tan\(\theta\) as changes from 00 to 900. i.e., \({0^0} \leqslant \theta \leqslant {90^0}\)
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TRIGONOMETRIC RATIOS Some standard angles : \(f(-\theta)\) for all the values of ‘\(\theta\)’: \(\begin{gathered} \sin \left( { - \theta } \right) = - \
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TRIGONOMETRIC RATIOS Trigonometric function of complementary angles 1. Consider a right angled triangle ABC, right angled at B. Let \(\angle A = \theta \) then \(\angle C = \left( {90 - \theta
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TRIGONOMETRIC RATIOS Properties of Triangle : 1. A triangle has 3 sides, 3 vertices, and 3 angles. 2. The sum of all the interior angles of a triangle is always equal to , it is known as the angle
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DISTANCE,DISPLACEMENT,SPEED &VELOCITY Introduction Kinematics is the science of describing the motion of objects using words, diagrams,numbers, graphs
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DISTANCE,DISPLACEMENT,SPEED &VELOCITY Distance & Displacement: Distance and displacement are two quantities that may seem to mean the same thing yet have distinctly differ
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DISTANCE,DISPLACEMENT,SPEED &VELOCITY Speed: Speed is the distance travelled per unit of time. It is how fast an object is moving. Speed is the scalar quantity that is the magnitud
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DISTANCE,DISPLACEMENT,SPEED &VELOCITY Velocity: Velocity is defined as a rate of change of displacement. In a simple, velocity specifies speed of body and its direction. The s
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Newton's 1st Law Of Motion INTRODUCTION In unit II,we studied the kinematics of motion by developing the concepts of displacement velocity and acceleration and by deriving rela
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Newton's 1st Law Of Motion NEWTON’S FIRST LAW OF MOTION OR LAW OF INERTIA Newton’s first law of motion states that every body continues in its state of rest or of u
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WORK In ordinary language the word ‘’Work’’ means any physical or mental activity but in physics, Work is said to be done by a force if the point of application of force
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WORK NATURE OF WORK ¶¶ POSITIVE WORK: &nb
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Newton's 2nd Law Of Motion 1. The rate of change of momentum of a body is directly proportional to the external force and the change in momentum takes place in the direction o
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NEWTON’S THIRD LAW OF MOTION To every action there is always an equal and opposite reaction Action and reaction do not occur on the same body they act on differe
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NEWTON’S THIRD LAW OF MOTION Law of conservation of linear momentum Collision: If a number of bodies collide with one another then total momentum of the bodies, just before collisi
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Energy "Energy of a body is it’s capacity to do work" Greater the amount of energy possessed by the body, greater the work it will be able to do. All the agents which are able to
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Energy Kinetic Energy The energy possessed by a body by virtue of its motion is called kinetic energy. Examples for body having kinetic energy ; (i) Flowing water possesses kinetic en
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Energy Potential Energy Potential energy of a body is the energy possessed by a body by virtue of its position or configuration * It is measured by the work that the body can do
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Power Power 1. Power is the rate of doing work. It is scalar. 2. Power =\( \frac{{workdone}} {{time}}\, = \,\frac{W} {t} \) 3. Uni
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Power Applications of Power 1) If a machine gun fires 'n' bullets per second such that mass of each bullet is 'm' and comming out with a velocity 'v' then the po
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Reflection From Mirrors Light: It is a form of energy. It enables us to see objects. It cause
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Reflection From Mirrors LAWS OF REFLECTION The angle between incident ray and normal to the reflecting surface is called angle of incidence(i) The angle between reflected ray and normal to the
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Reflection From Mirrors REFLECTION OF LIGHT ON A SPHERICAL SURFACE Spherical Mirror: Mirrors having curved reflecting surface are called spherical mirrors. A spherical mirror is a par
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Reflection From Mirrors RULES FOR IMAGE FORMATION BY SPHERICAL MIRROR AND RAY DIAGRAM The intersection of at least two reflected rays give the position of image of the point object. Any two
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Reflection From Mirrors Concave mirror: Reflection takes place at concave surface, Focal length of it is negative, It is a converging mirror, It has a real focus Uses of Conca
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Reflection From Mirrors Convex mirror: Reflection takes place at convex surface, Focal length of it is positive. It is a diverging mirror, It has a virtual focus. Uses of Convex Mirror:
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Refraction Of Light When a beam of light is travelling from one medium to another medium, a part of light gets reflected back into firstmedium at the inferface of two media and
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Refraction Of Light REFRACTIVE INDEX: I)Absolute refractive Index (µ): The absolute refractive index of a medium is the ratio of speed of light in free space (C) to speed of light in a give
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Refraction Of Light OPTICAL PATH (\( \Delta \)x): The shortest distance between any two points A and B is called geometrical path. The length of geometric path is independent of the medium that
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Refraction Of Light REAL AND APPARENT DEPTHS(NORMAL SHIFT) As a consequence of refraction, the depth of an object lying inside an optically denser medium appears t
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Refraction Of Light LATERAL SHIFT Consider a glass slab bounded by parallel faces XY and X’Y’ and of thickness t as shown in figure. A ray of light travelling in air
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SOUND Sound:- Sound is a form of energy which emitted by a vibrating body that travels in the form of waves and causes the sensation of hearing sound cannot travel through vacuum.
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SOUND Characteristics of sound:- Pitch:- 1. The pitch of a sound is the characteristic which distinguishes between a shrill (or sharp) sound and a grave (or flat) sound. 2. A sound of high pi
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Eye Human Eye The eye is probably the most important optical instruments. In principle, an eye can be compared to a photographic camera. In a camera, the aperture of the lens has to be adjusted. B
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SOUND Variation of velocity of sound in a gas with temperature. The velocity of sound in a gas v = \(\sqrt {\frac{{\gamma p}}{\rho }} \) \(v = \sqrt {\frac{{\gamma p}}{\rho }} = \sqrt {
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Eye Defects Of Vision A person with normal sight can see clearly the objects lying between near point and the far part (infinity for a normal eye). The distance betwee
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PRESSURE A liquid exerts pressure.To show it,consider a vessel containing a liquid.If it has a small hole near the bottom,the liquid will flow out of it.If the motion of the liquid is stopped by pres
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PRESSURE ATMOSPHERE AND ATMOSPHERIC PRESSURE The earth is surrounded by a gaseous envelope extending upto a few thousand kilometres.This gaseous envelope is made of 78% nitrogen,21% oxygen and a sma
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Gravitation UNIVERSAL LAW OF GRAVITATION : NEWTON’S LAW According to this law "Each particle attracts every other particle. The force of attraction between them is directly proportional
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PRESSURE ARCHIMEDES PRINCIPLE It states that when a body is immersed completely or partly in a liquid ,it loses in weight equal to the weight of the liquid displaced by it Let w1
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Gravitation RELATION BETWEEN G AND g We want to measure g due to M at a point P as per the procedure. Place a point mass m at P measure the force imparted by M on the test mass m. this is
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PRESSURE When a body is thrown into a liquid,one of the following may happen When a body of density and volume V is immersed in a liquid of density ,the force is acting on the body are: (1) W
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UNITS AND DIMENSIONS INTRODUCTION “MEASUREMENT” is the determination of the size or magnitude of something. Measurement can also be defined as “Comparison of an unknown quant
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UNITS AND DIMENSIONS TYPES OF PHYSICAL QUANTITIES Any quantity which can be measured directly (or) indirectly (or) in terms of which any laws of physics can be expressed is called physical qua
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UNITS AND DIMENSIONS UNITS AND TYPES OF UNITS Normally each physical quantity requires a unit or standard for its specification so it appears that there must be as many units as there are phys
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UNITS & DIMENSIONS - FACTORS AND PREFIXES MULTIPLE AND SUB-MULTIPLE FACTORS Multiples and submultiples are the prefixes and suffixes that we frequently use to express or show quantities in
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UNITS & DIMENSIONS - FACTORS AND PREFIXES Practical Units (1) Length : (i) 1 fermi = 1 fm = 10–15 m (ii) &n
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Units & DIMENSIONS - AREAS AREA OF REGULAR OBJECTS In geometry, the area can be defined as the space occupied by a flat shape or the surface of an object. The area of a
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Units & DIMENSIONS - AREAS AREA OF CIRCLE In geometry, the area enclosed by a circle of radius r is \(\pi\) r2. Here the Greek letter Srepr
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UNITS & DIMENSIONS - AREAS AREA OF A SQUARE If ‘a’ denotes the side of the square, then, length of each side of a square is ‘a’ units, then the perimeter and area of squa
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UNITS & DIMENSIONS - AREAS AREA OF RECTANGLE The formula of perimeter and area of rectangle are explained step-by-step with solved examples. If l denotes the length and b denotes the breadth of
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UNITS & DIMENSIONS - AREAS Area Of Triangle * If a, b, c are the sides of the triangle, then the perimeter of triangle = (a + b + c) units. * Area of the trian
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UNITS & DIMENSIONS - AREAS CONVERSIONS Relation between the various units of area Length Units
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Units & Dimensions - VOLUME VOLUME OF REGULAR OBJECTS Volume is the amount of space an object occupies while density is the mass of an object per unit volume. You need to know the volume of
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Units & Dimensions - VOLUME VOLUME OF A SPHERE A Sphere is a set of points in space that are a given distance ‘r’ from the center.The volume of a 3
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Units & Dimensions - VOLUME VOLUME OF CYLINDER The volume of a cylinder is the density of the cylinder which signifies the amount of material it can carry or how much amount of any material
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Units & Dimensions - VOLUME VOLUME OF CUBE The volume of a cube defines the number of cubic units that are occupied by the cube completely. A cube is a solid three-dimensional figure, which
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Units & Dimensions - VOLUME VOLUME OF CUBOID A cuboid is a three-dimensional structure having six rectangular faces. These six faces of cuboid exist as a pair of three pa
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Units & Dimensions - VOLUME UNITS OF VOLUME
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Units & Dimensions - VOLUME CONVERSIONS OF UNITS OF VOLUME
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Units & DIMENSIONS - DENSITY & RELATIVE DENSITY Definition of Density: Density is a word we use to describe how much space an object or substance takes up (its volume) in
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Units & DIMENSIONS - DENSITY & RELATIVE DENSITY SOLVED EXAMPLES Example 1: Take a brick of salt measuring 10.0 cm x 10.0 cm x 2.0 cm, which weighs 433 grams. Find the den
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Units & DIMENSIONS - DENSITY & RELATIVE DENSITY FACTORS AFFECTING DENSITY The 4 factors affecting the density of matter are 1. Mass 2. Volume&nb
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Units and DIMENSIONS - DENSITY and RELATIVE DENSITY DENSITY AND RELATIVE DENSITY Density of Water: As discussed, the density of a material is defined as its mass per un
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Units & DIMENSIONS - DENSITY & RELATIVE DENSITY SOLVED EXAMPLES Example 1: Find relative density of asteel ball of density20 g/cm3. Solution: S
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KINEMATICS- DISTANCE AND DISPLACEMENT Introduction: Kinematics is the science of describing the motion of objects using objects, diagrams, numbers, graph
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KINEMATICS-DISTANCE & DISPLACEMENT REST AND MOTION ARE RELATIVE A body can be both at rest and in motion at the same time. A body can be in motion relative to one set of objects while
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KINEMATICS - DISTANCE AND DISPLACEMENT DISTANCE AND DISPLACEMENT Distance and displacement are two quantities that may seem to mean the same thing yet have distinctly different definitions and
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KINEMATICS-DISTANCE & DISPLACEMENT Distance & Displacement in Motion in straight path Displacement is the shortest distance between two points, while distance is the length of the path trave
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KINEMATICS - SPEED AND VELOCITY Speed: Speed is the distance travelled per unit of time. It is how fast an object is moving. Speed is the scalar quantity that is the magnitude of the v
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KINEMATICS - SPEED AND VELOCITY SOLVED EXAMPLES Example 1: In travelling from Pune to Nagpur, Rahul drove his bike for 2 hrs at 60 kmph, 3 hrs at 70 kmph.Find his average speed.
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KINEMATICS - SPEED AND VELOCITY VELOCITY Velocity is defined as a rate of change of displacement. In a simple, velocity specifies speed of body and its direction. The speed of a car traveling north
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KINEMATICS - SPEED AND VELOCITY Speed vs Velocity: Speed is the distance travelled per unit of time. It is how fast an object is moving.
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Units And Dimensions-Physical Quantities INTRODUCTION: PHYSICAL QUANTITIES: A quantity which can be measured and by which various physical happenings can
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KINEMATICS-ACCELERATION ACCELERATION Acceleration is defined as the rate of change of velocity with respect to time.Acceleration is a vector quantity as it has both magnitude as
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KINEMATICS -ACCELERATION TYPES OF ACCELERATION There are different types of accelerations are there. Out of those, some of the types we will discuss here. 1. Positive Acceleration
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Units And Dimensions-Physical Quantities UNITS & TYPES OF UNITS Systems of Units : There are four systems of units 1. F.P.S 2. C.G.S&n
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KINEMATICS - ACCELERATION Acceleration due to gravity(g): What is Gravity? Gravity is the force with which earth attracts a body towards its center. Acceleration due to gravity(g):
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Units And Dimensions-Physical Quantities MULTIPLE & SUB-MULTIPLE FACTORS: Prefixes for multiples and submultiples of units are used to more conveniently express very large a
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Average speed,Average Velocity & Acceleration DISTANCE AND DISPLACEMENT Distance and displacement are two quantities that may seem to mean the same thing yet have distinctly different defi
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Average speed,Average Velocity & Acceleration Speed: Speed is the distance travelled per unit of time. It is how fast an object is moving. Speed is the scalar quantity that i
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Average speed,Average Velocity & Acceleration VELOCITY Velocity is defined as a rate of change of displacement. In a simple, velocity specifies speed of body and its direction. The speed o
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Average speed,Average Velocity & Acceleration Acceleration: Acceleration is defined as the rate of change of velocity with respect to time. Accelerati
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Dimensional Formula Dimension: Dimensions of a physical quantity are the powers to which the base quantities are raised to represent one unit of that quantity. The dimensions of
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Distance, Displacement, Speed and Velocity Introduction Kinematics is the science of describing the motion of objects using words, diagrams,numbers,
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Distance, Displacement, Speed and Velocity Distance: The path length covered by the body is called distance.it is a scalar quantity. Units: cm (In C.G.S. System); m(In S.I. System) Dis
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Dimensional Formula Dimensional formula for some other physical quantities: Charge, (q) = [AT] Specific heat, (s) = [L2T2K-1] Gas constant, [R] = [ML2T-2K-1 mol-1] Rules for writing dimension
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Distance, Displacement, Speed and Velocity Speed: Speed is the distance travelled per unit of time. It is how fast an object is moving. Speed is the scalar quantity that is the magnitu
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Distance, Displacement, Speed and Velocity Velocity: The rate of displacement (or) displacement per unit time is called velocity. * The velocity of a body can n
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Dimensional Formula IMPORTANT DIMENSIONAL FORMULAE Dimensional Constants: The physical quantities which have dimensions and have a fixed value are called as dimensional constants. Ex: Gravitat
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Vectors-Types And Components VECTORS - TYPES & COMPONENTS All measurable quantities are called physical quantities. Physical quantities are classified into scalars and vectors. S
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Vectors-Types And Components Types of vectors 1) Equal vectors: If two vectors have same magnitude and direction they are said to be equal vectors. 2) Like vectors or Parallel vectors: If
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Vectors-Types And Components Angle between two vectors: To find angle between two vectors, the two vectors from a point are drawn such that they should either co init
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Vectors- Types And Components Displacement and Displacement vector Displacement is a shortest distance between two points. It is a vector quantity. &n
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Basics Of Trigonometry Trigonometry plays an important role in physics, which takes you to a different level in understanding physics Introduction:  
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Basics Of Trigonometry Trigonometric Function and Ratios: In the figure OMP is a right angled triangle(Let the initial line OX revolves and trace out an angle ¸ Take a
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Basics Of Trigonometry Trigonometric Ratios of Particular Angles: In the above picture if triangle is drawn for an angle for which ever side lenghts we get always Hypotenuse length
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Quadrants And Graphs Quadrants: Two mutually perpendicular straight lines XOX’ and YOY’ divide the plane into four equal parts, each part is called quadrant. Thu
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Quadrants And Graphs Signs of Trigonometric Functions: The trigonometric ratios discussed above have different signs in different quadrants. We can remember the sign of trig
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Quadrants And Graphs Important trigonometric functional relationships Example 1: sin 120° = sin (190°+30°). Here n = 1, an odd integer. Sin changes to Cos &
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Angle Between Vectors And Magnitude of Vectors VECTORS - TYPES OF VECTORS Physical quantities : The quantities that are measurable are called physical quantities Ex: Length, Mass
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Angle Between Vectors And Magnitude of Vectors The angle between two vectors is represented by the smaller of the two angle between the vectors when they are placed tail to tail by displacing either
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Displacement and Displacement vector Displacement is a shortest distance between two points. It is a vector quantity. The position of the point Q w
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parallelogram law of vectors Two vector quantities can be added using parallelogram law ( velocity vector can be added to velocity vector only). This law is useful to find both magnitude and di
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Resolution Of Vectors Into Components And Types Of Vectors Components of a vector Any vector can be expressed as the vector sum of some other vectors known as component vectors
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Resolution Of Vectors Into Components And Types Of Vectors Direction cosines : If \( \alpha ,\beta ,\gamma \) are angle made by \( \bar A \) with x, y, z axes, then \( \cos \alpha ,
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DISTANCE,DISPLACEMENT,SPEED & VELOCITY INTRODUCTION Many objects that physicists study from atoms to galaxies are in motion. Motion may be orderly or random, steady or intermittent or even a con
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DISTANCE,DISPLACEMENT,SPEED & VELOCITY DISPLACEMENT "The shortest straight line distance directed from initial position to final position irrespective of the path is called displacement&quo
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DISTANCE,DISPLACEMENT,SPEED & VELOCITY Speed: The distance travelled by the body in unit time is called its speed. Speed (V) = \(\frac{{Dis\tan ce\,\,t
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DISTANCE,DISPLACEMENT,SPEED & VELOCITY VELOCITY The displacement of a body in unit is called it's Velocity. It is a vector quantity. CGS unit is cms-1 SI unit is .ms-1 Dimensional formul
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Trigonometry And Differentiation Trigonometric Ratios and Differentiation Trigonometry:Trigonometry plays an important role in physics, which takes you to a different level in understanding
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ACCELERATION AND EQUATIONS OF MOTION ACCELERATION If the velocity of a particle is changing as it moves then it is said to be moving with acceleration. The acceleration measures how
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ACCELERATION & EQUATIONS OF MOTION GRAPHICAL TREATMENT: KINEMATICAL EQUATIONS OF MOTION OF A BODY WITH UNIFORM ACCELERATION Consider a particle moving with initial velocity 'u
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PARALLELOGRAM LAW OF VECTORS Statement : If two vectors are drawn from a point so as to represent the adjacent sides of a parallelogram both in magnitude and the direction, the diagonal of the parall
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TYPES OF VECTORS AND COMPONENTS All measurable quantities are called physical quantities. Most of the physical Quantities are classified into 'Scalars' and 'Vectors'. Scalar:- Physic
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TYPES OF VECTORS AND COMPONENTS TYPES OF VECTORS a) Polar Vectors: The vector whose direction does not change even though the coordinate system in which it is defined changes is called polar vector
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Trigonometry And Differentiation DIFFERENTIATION: Sir Isaac Newton and Gottfried Wilhem Leibnitz developed calculus. Constant quantity: If the value of a quantity remains the same in a mathe
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Types Of Vectors RESOLUTION OF A VECTOR INTO RECTANGULAR COMPONENTS Resolution of a vector is the process of obtaining the component vectors which when combined, according to laws of vector additi
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HEAT - TEMPERATURE AND SCALES Real time Applications: * In medical field thermometers are used by the doctors to know the temperature of a patient. * In industri
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HEAT - TEMPERATURE AND SCALES Thermometer: * It is a device used for measuring the temperature of different objects. * First thermometer was invented by Galile
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HEAT - TEMPERATURE AND SCALES Thermometric Scales : 1) Celsius (or) Centigrade Thermometer: * This scale was introduced by Celsius. * On this scale00C r
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HEAT - HEAT CAPACITY Heat capacity (or) Thermal capacity (C) : The amount of heat energy required to raise the temperature of a given mass of a substance through 10C.
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Newton’s First Law Of Motion Real time Applications: Importance of seatbelts headrests and airbags in vehicles is the application of I law only Inertia e
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Newton’s First Law Of Motion INERTIA: Inertia is the property of a body by which unable to change it’s state by it’s own mass is measure of inertia force is that which changes or te
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Linear momentum :- Consider two balls A and B. Let ball A be heavier than the ball B. i.e. mass (m1) of ball A is greater than the mass (m2) of the ball B. Suppose both balls
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NEWTON’S SECOND LAW OF MOTION 1. The rate of change of momentum of a body is directly proportional to the external force and the change in momentum takes place in the directio
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NEWTON’S SECOND LAW OF MOTION Change of momentum : If ‘u’ and ‘v’ are the initial and final velocity of a body then its, initial momentum = mu final mom
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SYMBOLS AND FORMULE Introduction : In order to represent the elements, instead of using full lengthy names, scientists use abbreviated names. These abbreviated names of the
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SYMBOLS AND FORMULE List of Elements with Name, Atomic number and Symbol
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Valency,Ions When atoms of two or more elements combine, a molecule of a compound is formed. The capacities of these elements to combine with each other determine the formula of the compound formed.&
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Valency,Ions Let's explore how valency changes in groups when elements combine with hydrogen: Group 1 (Alkali Metals): Elements in Group 1, such as lithium (Li), sodium
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Valency,Ions Let's explore how valency changes in different groups when elements combine with oxygen Group 1 (Alkali Metals): Elements in Group 1, such as lithium (Li), sodiu
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Valency,Ions Let's explore how the valency changes in different groups when elements combine with chlorine Group 1 (Alkali Metals): Elements in Group 1, such as lithium (Li),
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Valency,Ions Modern Definition of Valency : According to the new concepts, Valency can be defind as the number of electrons that are lost or gained or shared wi
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Valency,Ions Nuclear Composition of Elements
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Valency,Ions Electronic Configuration of Elements
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Valency,Ions Valence electrons: The electrons in the outermost shell of an atom are called its valence electrons. Example : The number of valence electron in sodium i
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Valency,Ions Radical or Ion When an atom looses or gains electrons it converts into Radical or Ion. (or) An atom or group of atoms with charge on them is called Radical or ion (ii) Classifica
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Electropositive Ions Radical or Ion : When an atom looses or gains electrons it converts into Radical or Ion. (or) An atom or group of atoms with charge on them is called Radical or ion (ii) Clas
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Valency,Ions Concept of Variable Valency Most elements such as Na, K, Mg, Al, Ca, Ba etc..exhibit a fixed valency in all their compounds, Sometimes the same element may form two or more differ
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ELECTRONEGATIVE IONS Electronegative ions are negatively charged ions that are formed when an atom gains one or more electrons during a chemical reaction. The term "electronegativity" refer
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ELECTRONEGATIVE IONS Properties Of Electronegative Ions Electronegative ions, or anions, have several characteristic properties. These properties arise from the fact that anions a
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Electropositive Ions Electropositive ions When an atom looses one or more electrons to get stability, The number of electrons lost by an atom of an element is
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Electropositive Ions Monovalent electropositive ions When an atom looses one electron or if any Radical or ion has uni positive charge on it then it is known as Monovalent elect
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ELECTRONEGATIVE IONS Monovalent negative ions:A radical formed when an atom gains one electron is called monovalent negative ions. Illustration 2: If in an element X there a
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ELECTRONEGATIVE IONS Trivalent Electronegaive ions A Radical or Ion which is formed by gaining of three electrons is called Trivalent Electronegaive ions. Tetravale
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ELECTRONEGATIVE IONS Trivalent Electronegaive ions A Radical or Ion which is formed by gaining of three electrons is called Trivalent Electronegaive ions. Tetravale
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Electropositive Ions Trivalent electropositive ions When an atom looses three electrons or if any Radical or ion has tripositive charge on it then it is known
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Electropositive Ions Concept of Variable Valency Most elements such as Na, K, Mg, Al, Ca, Ba etc..exhibit a fixed valency in all their compounds, Sometimes th
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FORMULA The symbolic representation of one molecule of a compound representing the number of atoms of various elements present in it is called formula o
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FORMULA Naming chemical compounds from their fromula Usually the elements present in a compound are named in order of symbols appearing in formula. Follow
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Naming of Acids And Bases Naming acids involves specific rules based on the type of acid: binary acids or oxyacids. Below are the general rules for naming acids Binary Acids: &nb
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Mole Concept Mole Concept We shall first recap of concepts learnt in previous classes about Atoms, Molecules, Elements, Compounds and Mixtures. - Atom: Atom is the smallest particle of an element
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Mole Concept MOLE: A number of methods are available for measuring the quantity of a given substance. The quantity of substances is expressed either in the units of weight (Example 1 gram, 1 Kg et
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Mole Concept Solved Examples Example: Calculate the number of moles of H, S and O in 5 moles of H2SO4. Solution: 1 molecule of H2SO4 contains 2 atoms of H, 1 atom of S and 4 atoms
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Atomic Weight Molecular Weight Atom and Atomic Weight The smallest particle of an element that takes part in chemical reaction is called atom. An atom is so minute that it cannot be detected
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Atomic Weight And Molecular Weight Relation between atomic weight in amu and Gram Atomic Weight Lets consider an example Based on the experimental results on weighing 1 atom of Aluminium &
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Atomic Weight And Molecular Weight Molecular Mass or Molecular Weight Molecular mass or Molecular Weight is the sum of atomic masses of all atoms of elements in a molecule. Steps to calculate th
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Atomic Weight And Molecular Weight Relation between molecular weight in amu and Gram Molecular Weight Lets consider an example Based on the experimental results on weighing 1 molecule of Sodium H
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Atomic Weight And Molecular Weight Relationship between mole, Avogardro number and mass
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Atomic Weight And Molecular Weight Gram molecular volume(GMV): The volume occupied by 1 gram molecule of a dry gas at S.T.P. conditions is called Gram Molecular Volume. NOTE: S
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Atomic Weight And Molecular Weight SOLVED EXAMPLES Q. Calculate the number of molecules of sulphur (S8) present in 16 g of solid sulphur. Ans. Mass of 1 mole o
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Changes Around Us-Physical And Chemical change, Characteristics §§ Physical and chemical changes: All substances around us undergo changes.
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Changes Around Us-Physical And Chemical Change, Characteristics Some Easy Physical Change Experiments There are quite a few easy experiments that you can carry out at home or in your school lab to
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Changes Around Us-Physical And Chemical Change, Characteristics Characteristics of physical change : 1) No new substances are formed during physical change.
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Changes Around Us-Physical And Chemical Changes, Characteristics Chemical Change A chemical change is one where there are changes in the chemical properties of the components. Their chemical compo
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Changes Around Us-Physical And Chemical Change, Characteristics Experiments to Show Chemical Changes: Burning of Magnesium ribbon: When a small piece of a thin strip or ribbon of magnesium cleaned
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Changes Around Us-Physical And Chemical Change, Characteristics Characteristics of a chemical change: 1) When a chemical change occurs new substances, with entirely new properti
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COMBINATION AND DECOMPOSITION REACTIONS Definition of chemical change: A change in which new substances are formed is called Chemical change. Ex:  
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COMBINATION AND DECOMPOSITION REACTIONS CHEMICAL DECOMPOSITION REACTIONS A decomposition reaction is a type of chemical reaction in which a single compound breaks down into two or more eleme
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DISPALCEMENT AND DOUBLE DECOMPOSITION REACTIONS CHEMICAL DISPALCEMENT REACTIONS A single-displacement reaction, is a chemical reaction in which one (or more) element(s) replaces an/other
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DISPALCEMENT AND DOUBLE DECOMPOSITION REACTIONS Chemical displacement reactions can be further classified as Metal displacement reaction: A chemical displacement reaction i
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DISPALCEMENT AND DOUBLE DECOMPOSITION REACTIONS DOUBLE DISPLACEMENT REACTIONS A double displacement reaction is a type of reaction in which two reactants exchange ions to form two new compound
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DISPALCEMENT AND DOUBLE DECOMPOSITION REACTION Formation of a Precipitate in a double-displacement reaction A precipitate forms in a double-displacement reaction when the cations from one of the rea
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Preparation And Properties Of Acids Acids: Substances with sour taste and changing blue litmus to red are called acids. The term acid has been derived from Latin word acidus, whic
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Preparation And Properties Of Acids Definition of Acid: Acid is defined as a substance which gives out hydrogen ions when dissolved in water.  
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Preparation And Properties Of Acids Preparation of acids: 1. From Non metals. Elements such as carbon, sulphur, phosphorous etc. are burnt in oxygen and
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Preparation And Properties Of Acids Physical Properties of acids: i) All the acids are colourless, though sulphuric acid may be brown at times due to impurities. ii) &
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Units And Measurements PHYSICAL QUANTITIES All the quantities which are used to describe the laws of physics are known as physical quantities. OR The quantities which are measurable are called p
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Units And Measurements @UNIT : That fixed and definite quantity which we take as our standard of reference and by which we measure other quantities of same kind, is defined as u
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Units And Measurements ØMultiples and sub multiples of Basic units:- The above mentioned International System of Units (SI) is now extensively used in scientific measurem
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Motion In A Straight Line Distance And Displacement Many objects that physicists study from atoms to galaxies are in motion. Motion may be orderly or random, steady or intermittent or even a confu
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Motion In A Straight Line Speed: The distance travelled by the body in unit time is called its speed. Speed (V) = \( \frac{{Dis\tan cetravelled}} {{Tim
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Motion In A Straight Line VELOCITY The displacement of a body in unit is called it's Velocity. It is a vector quantity. CGS unit is \( cms^{ - 1} \) SI unit is \( ms^{ - 1} \). Dimens
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Motion In A Straight Line Rest: An object is said to be at rest if it does not change its position with respect to its surroundings. In other words, the object's po
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Motion In A Straight Line Distance and displacement are concepts used to describe the motion of an object in physics. While they both refer to the location change of an object, they have distinct m
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Motion In A Straight Line Speed: Definition: Speed is a scalar quantity that measures the rate at which an object covers distance. It is the magnitude of the velocity vector.
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Motion In A Straight Line Velocity Formula: Velocity (v) is calculated as the ratio of the displacement (or )to the time taken (t): v=. &nbs
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Force And Pressure FORCE: A pull or push which changes or tends to change the state of rest or state of uniform motion of a body. it is a vector. C.G.S units are dyne &
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Force and Pressure NON CONTACT FORCES: 1.The Gravitational force.[G.F]It is the force of attraction between two objects due to their masses M1 and M2 is governed by Newton’s law of grav
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Force And Pressure PRESSURE A liquid exerts pressure.To show it,consider a vessel containing a liquid.If it has a small hole near the bottom,the liquid will flow out of it.If the motion of the liq
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Force And Pressure PRACTICAL APPLICATIONS OF THE KNOWLEDGE OF PRESSURE 1.paper-pins and nails are made to have pointed ends.Because of their pointed end,pins and nails have very small area .When f
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Motion In A Straight Line Rest: An object is said to be at rest if it does not change its position with respect to its surroundings. In other words, the object's po
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Motion In A Straight Line Distance And Displacement Many objects that physicists study from atoms to galaxies are in motion. Motion may be orderly or random, steady or intermittent or even a confu
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Motion In A Straight Line Speed: The distance travelled by the body in unit time is called its speed. Speed (V) = &nbs
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Motion In A Straight Line VELOCITY The displacement of a body in unit is called it's Velocity. It is a vector quantity. CGS unit is \( cms^{ - 1} \) SI unit is \( ms^{ - 1} \).
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Motion In A Straight Line If the velocity of a particle is changing as it moves then it is said to be moving with acceleration. The acceleration measures how rapidly the velocity is changing. Acce
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Motion In A Straight Line KINEMATICAL EQUATIONS OF MOTION OF A PARTICLE MOVING ALONG A STRAIGHT LINE WITH UNIFORM ACCELERATION Kinematical equations are useful to solve problems in one dimensional
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Light REFLECTION OF LIGHT ON DIFFERENT SURFACES: The property of bending of a light into the same medium after striking an obstacle is called reflection of light. Types of Refl
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Light Mirror: A mirror is an optically opaque material which forms the images by the phenomenon of reflection of light. Depending upon the it’s surface, mirrors are generally two in types
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Light Reflection of light on a plane mirror: Plane mirror: A smooth and highly polished plane surface is called a plane mirror. Actually a plane mirror is made from gla
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Light Reflection of light on a spherical surface Spherical Mirror: Mirrors having curved reflecting surface are called spherical mirrors. A spherical&
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Light Rules for image formation by spherical mirror and ray diagram The intersection of at least two reflected rays give the position of image of the point object. Any two of the following r
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Friction Real life applications * Walking: if there is no friction between your shoes or feet and the floor,you would be slippering in one place forever * Brea
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Friction METHODS OF REDUCING FRICTION *POLISHING : Friction can be reduced by making the surface in contact polished and smooth. This will remove th
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Friction TYPES OF FRICTION There are three types of frictional forces i. Static friction ii. Dynamic friction
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\( \mu \)Friction Types& Characteristics of static friction a)When there is no component of external force parallel to the two surfaces in contact with each other, the force of static frict
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Types Of Numbers Natural numbers : The counting numbers are known as natural numbers. Ex : 1, 2, 3, 4, 5 .............. Properties of Natural numbers: i)The first and the smal
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Multiples And Factors Introduction: * If a number ‘a’ divides another number ‘b’ exactly then we say that ‘b’ is called multiple of &lsq
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Integers And Absolute Values STORY ON PROPERTIES OF INTEGERS Once upon a time in the quaint town of Numerica, there lived four friends named Addy, Subby, Multi, and Divvy. The
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Counting 0 to 10 Concept of Zero ‘Zero’ (0) is a special number. If there are zero things, then there is nothing at all. For example, if a person has zero hats, that means they do not ha
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Counting 0 to 10 Numbers 1 - 10
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Counting 0 to 10 Number line Number lines are, in a sense, the address where a number lives. It helps children visualise the relationship of one number to another
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Counting 0 to 10 Before, After and In Between Number 3 is before number 4, Number 5 is after number 4, Number 4 is in between numbers 3 and 5
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Addition up to 10 Addition (+) Addition can be visualized as 'putting together' or two or more quantities. The addition is taking two or more numbers and adding them together. The sign f
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Addition up to 10 Addition on number line We learned about the number line in the previous chapter. Let us now learn how to add numbers using a number line Example: Move 5 steps from 0 and
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Addition up to 10 Addition by drawing strokes Let us add 3 and 2
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Addition up to 10 Properties of Addition Addition of one (1) When one (1) is added to a number, the answer is the number that comes just after the given number Addition of zero (0) Whe
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Addition up to 10 Addition of three numbers
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My Introduction Hello friends, let me introduce myself... 1.My name is _______________. 2.My age is ______________ years. 3.My mother’s name is _______________. 4.My f
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My Introduction My Identity Card Name &n
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My Introduction My good habits. Studying together. Playing together. Others good habits. Standing in queue. Kindness to animals. Throwing trash in dustbin. Brush your teeth twi
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Subtraction (―) Subtraction is the process of taking a number from another. It is denoted by a subtraction symbol (―). Let us understand the subtraction formula The subtraction f
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Subtraction (―) Subtraction using strokes Draw the number of minuend strokes, then strike the number of subtrahend strokes, and count the difference. Draw and cross the lines and then subtr
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Our Body Body Parts Our body is a wonderful system made up of different parts. Look at the picture given below and learn about some of the body parts:
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Subtraction (―) Number Story Substraction
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Numbers upto 20 Numbers 11 – 20 We will learn numbers and count up to 20 to recognise the numerals 11 through 20
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Numbers upto 20 Place Value of a Digit The place value of a digit in a number is the value it holds to be at the place in the number. Let us take a 2-digit number 15 In 15, 1 is in the
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Numbers upto 20 Expanded form of a Number In expanded form of a number, the number is shown according to the place values of its digits. This is shown here: In 18, the place values o
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Our Body Functions of Body Parts How do we come to know about these things. I see things with my eyes. I smell flowers with my nose. I taste food with my tongue. I feel things
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Numbers upto 20 Short form of a Number The short form of a number is a way of expressing the expanded form in figures. For example, the short form of
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Our Body Five Sense Organs Different parts of our body perform different tasks.
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Numbers 20 - 30 Numbers 21 – 30
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Integers And Absolute Values Addition of integers As we already know addition of any two numbers a and b means moving b units to right of a on the line. The same is followed even in the addition o
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Numbers 21 – 30 Numbers 31 – 50
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Numbers 50 to 100 Abacus concept This is an abacus. It has two sticks Stick 1 is ones place value. Stick 2 is tens place value. Beads are used to indicate digits in the ones and tens sticks. Max
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Numbers 50 to 100 Numbers up to 100 Now, let us learn 50 to 70 numbers using the abacus Now, let us continue learning 70 to 100 numbers using the abacus
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Integers And Absolute Values Properties of addition in Integers 1. Closure Property Observe the following 1. 25+75 = 100 2. 10
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Comparison of Numbers Greater Than and Less Than Observe the birthday caps and answer the following questions : How many big birthday caps are there? 3 How many small birthday caps are the
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Comparison of Numbers Rules of Comparison of Numbers Here are some rules to compare 1-digit and 2-digit numbers: Rule 1: A 2-digit number is always greater than a 1-digit number For Exampl
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Integers And Absolute Values Substraction of Integers Substraction of any two integers a and b is . The substraction of Integers follows the rules of signs:- i) \( a - ( + b) = a - b \) &
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Ordering of Numbers Smallest to Greatest (Ascending Order) The vehicles shown below are parked from the smallest to the greatest In the same manner, we can arrange the numbers from the sm
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Integers And Absolute Values Properties of substraction of Integers 1. Closure Property:- Observe the following 1. 25-75=-50 2. \(% MathType!MTEF!2!1!+- % feaaeaart1ev0aaatCvAUfeBSjuyZL2y
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Integers And Absolute Values Multiplication of Integers Let a and b are any two integers then i)\( ( + a) \times ( + b) = + ab,\,\,\,ex:( + 7) \times ( + 6) = + 42 \) ii)\( ( +
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Integers And Absolute Values Division of Integers let us see the rule given below which helps us in performing the division operation over integers. Rule I :- The quotient of t
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Good Habits Good health keeps us strong and active. It keeps us fit. When we are healthy, our minds also work better. Keeping ourselves clean is called cleanliness. Some good habits are: &bul
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Good Habits • Eat your meals at the table with your family. • Every day, have a bath with soap and water. • Wear clean and well ironed clothes. • Do class assignments d
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Good Habits • We comb our hair to keep them clean. • We clean dirt off our nails by cutting them. • A dirty habit is poking your nose. Hope you don’t do it. Clean yo
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Good Habits Good Eating Habits Some good eating habits are- Drinking 6-8 glasses of water and 1-2 glasses of milk daily. Washing our hands before and after eating. Eating different kinds of foo
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My Family Family: Introduction My home is in a city, where I live with my father, mother, brother and sister. My grandfather and g r a n d m o t h e r live in a village near the city. Whenever the
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My Family Types of Families Small family We all live in a family. Father, mother and children make a family. Father and mother together are known as parents. This is Nicholas’s family. He l
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My Family Why is a family important to us? A family is very important to all of us. • We help each other and share work at home. • We love every one in the family. • We support o
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Our Food About Food We need food to stay alive. We take breakfast in the morning. In the breakfast, we eat Dosa with egg and drink milk. We take our lunch in the afternoon after coming back from o
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Our Food Types of food that we eat We eat a lot of different things. Food that protects us from sickness Food that keeps us healthy Food that helps to grow Food that gives energy Heal
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Our Food Food from plants 1. We get most of our food from plants. 2. Plants give us vegetables and fruits. 3. Plants give us cereals and pulses. 4. We also get coffee, tea and sugar from plants
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Our Food Pulses Moong, Arhar, Gram, Peas, Rajmah, Beans and Soyabean are some of the pulses we eat. Food Grains Cereals and pulses together are called food grains. Plants give us spice
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Our Food Food from animals
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Games Games at school As soon as the bell for break rang, we came out of our classroom. All the students reached the playground. In the ground, there are many places to play. Some students started
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Games Indoor games Games that we play inside our home are called indoor games. Chess, Ludo, Snake and Ladders, Carrom and Cards etc are some common indoor games.
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Games Outdoor games Games that we play outside our home or in the playground are called outdoor games. Football, Cricket, Basketball, Volleyball, Hockey and Kho-Kho etc are some common outdoor games
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School School: Introduction I study in a school near my home. Our school is very beautiful. There are eight classrooms and a playground in the school. There are flowers and trees in the school. Th
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School Different rooms of a School The main room in a school is the Principal’s office from where he/she works. Teachers sit in the staff room in their free time and check notebooks.
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School Daily routine in the school There are ten teachers in our school. There is a gardener who looks after the plants. The headmaster controls all the school activities. We respect our
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Health Health: Introduction God has blessed us with good health. We should take care of cleanliness. If we don't take care of cleanliness, we shall become ill. When we become ill, we
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Health Some common diseases: 1. Cough 2. Measles 3. Malaria Some diseases are caused by germs. These germs are present on different things. When we touch these things, germs stick to our hands. Wh
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Health Good habits to keep us healthy We should take care of the following to keep us health. Trash litter &
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Childhood Playtime And when the rain had gone away And sun was shining everywhere, I ran out on the walk to play And found a little bug was there. And he was running just as fast As any litt
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A Neat And Tidy Home I am Mary. I am a girl. This is my home, i live in it with my family. I have two brothers and a sister. My home is my favorite place. It is very airy and beautiful. It has two
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A Neat And Tidy Home We sit together and watch television in the sitting room. We discuss and share many things. We always keep our home neat and clean. I live in New Delhi. It is the capital
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Seed Becomes A Plant It is Sunday morning. Henry is in his grandfather’s garden. He loves greenery all around. “Good morning, grandfather. What are you doing?” asks Henry. “
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A Snake A snake can glide from side to side. They’re really long and like to hide. They have long backbones, but no hair. They use their tongues to taste the air. They taste your scen
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Gender Equality The clock slowly ticks away. It is Sunday and Sara is bored. She has nothing to do. Her brother John has his final exams next week. He is busy studying and cannot play with her. She
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Gender Equality Suddenly, John sees her and shouts, “Do not touch my books.” He snatches his book out of her hands. “But I want to read them too,”says Sara, with tears in
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Gender Equality Hearing their voices, their father enters the room and asks,“Why are you scolding your little sister, John?” “She is spoiling my books,father,” complains Joh
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Doing your own Work Peter mother has been sick for a few days now. When Peter comes back from school, he finds the house in a complete mess. No food is cooked, no washing is done and everything s
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Doing your own Work Peter cleans the rooms and dusts the furniture. They cook the food. They keep asking their mother for help In the evening, when their father enters the house, he is surpr
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Doing your own Work
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Nature It makes you healthy It gives you energy, An apple or a guava Have a fruit everyday But don’t throw the seeds away In time it will become a big tree Which gives
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Safety in Sports Alexander and his friends love sports period at school. Today, they are playing cricket. The match begins and Alexander’s team bats first. Alexander hits the ball in the air.
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Safety in Sports Alexander is worried but then he remembers what his father had told him about handling such situations. He helps John sit up on the grass. Alexander sends his friend, Ahmed,
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Keeping the Environment Clean Drip is a little fish. He lives in the river with many other fish. The big, blue flowing river is their home. For the past many weeks, Drip and his friends and fami
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Keeping the Environment Clean Drip’s sister Donna cannot breathe properly because her nose is blocked with mud and garbage. She is sneezing and she cannot breathe. Drip is worried to see his
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Traffic Lights
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Keeping the Environment Clean Drip listens to his father with a look of concern. He says, “But that trash and garbage is making us all sick! The humans must stop littering their home so our
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Manners Good Manners for Kids Let us read a poem about good manners Don’t forget to mind your manners Be polite, say “Thank you” please Don’t forget to blo
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Traffic Lights
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Traffic Lights
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The Truthful James and Jack are friends. They are also classmates. One day, James and Jack were in the class, waiting for their teacher. They were showing each other their erasers, colour pencils a
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The Truthful He ran to show it to his mother “Look, mother. This is James’s pencil box. I put it in my bag by mistake. Moral of the story: “Honesty is the best policy.” But!
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Fundamentals Of Fractions STORY OF FRACTIONS Once upon a time in the quaint village of Numerica, there lived two friends, Fred the Numerator and Denise the Denominator. Fred was always on the mo
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Fundamentals Of Fractions Fraction : A fraction represents a numerical value, which defines the parts of a whole. Generally, the fraction can be a portion of any quantity out of the whole th
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Fundamentals Of Fractions Fraction on a Number Line We have already learned to represent the integers, such as 0, 1, 2, -1, -2, on a number line. In the same way, we can represent fractions on a n
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Fundamentals Of Fractions Comparison Of Fraction Common Denominator Method: Find a common denominator for the two fractions. Convert both fractions to equivalent fractions with the common denomi
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Fundamentals Of Fractions How to arrange fractions in ascending and descending order: 1. Check the denominators of all the given fractions. If all the denomiantors are equal then simply compa
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Our Country India 1. National Flag Tiranga is the national flag of India, it was designed by Pingali Venkayya and was adopted by the assembly on 22nd July 1947. Tiranga means tricolor. There are t
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Our Country India 4. National Animal Royal Bengal Tiger is the national animal of India. It is an endangered animal therefore it was adopted as the national animal of india. 5. National Bird
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Our Country India 7. National Song Vande Mataram is the national song of India. It was written by Bankim Chandra Chatterjee. It was adopted by the assembly in 1950. 8. National tree Th
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The Government Parents are family heads. They take care of their children and their needs. In the same way, government also takes care of its people, and does a lot of work to meet the needs of the
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The Government Bank Banks are meant to deal with the procedures related to money. One can get loans, save money or get money using their accounts in a bank. Post Office The post office deals
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The Government Railway Station Like a bus stop, the railway station is where we find trains for different destinations and their schedule. A railway station is provided with the basic amenities fo
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Neat And Clean Environment Garbage Our surroundings include everything around us like plants, animals, houses, parks, roads and markets. Air, water and soil are also a part of our surroundings. An
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Neat And Clean Environment HOW TO DISPOSE OF GARBAGE We should throw garbage or rubbish in covered dustbins. The dustbins should be kept outside the houses. When we are in schools or outside in pa
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Neat And Clean Environment CLEANLINESS IN THE SURROUNDINGS Clean surroundings help us to live a healthy life. We can keep our surroundings clean in the following ways: Do not litter parks, scho
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Neat And Clean Environment STAYING FIT AND HEALTHY To be fit and healthy, we should do some exercise, maintain correct posture, play games and take good rest. • Exercise makes our muscles an
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Our Earth The only planet which we can touch is our earth. Earth, our home, is the third planet from the sun. It is the only planet known to have an atmosphere containing free oxygen, oceans of liq
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Our Earth Man Made Things There are many things which are made by man. They are called man made things. Man has made things to satisfy is needs. Man needs shelter, so he makes homes. Man also need
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Agriculture And Farming Agriculture is a primary activity. It includes growing crops, fruits, vegetables, flowers and rearing of livestock. We need food to stay alive and active and to do our work
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Agriculture And Farming Paddy Farming or Rice Farming Rice is the main crop. Other crops include wheat, maize, pulses and oil seeds. Paddy is also called rice paddy. A small level flooded field is
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Agriculture And Farming Wheat field or Wheat Farming At first, the wheat is green and can look like grass. Then it grows taller and becomes a golden brown color as it dries. Wheat products.
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Agriculture And Farming Cotton Farming The farmer grows cotton crop. Cotton is obtained from cotton crop. Thread is prepared from cotton. Cotton is a Kharif crop in the major parts of the country.
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Agriculture And Farming Farmers rear animals We get milk from buffaloes and cows. Dairy is a universal agricultural production people milk dairy animals in almost every country across the world, a
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Bricks Building,. Offices, houses, hospitals, sheds, flats - the list of building types you can create with bricks goes on and on. Cement Cement is mainly used as a binder in concrete, which is
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Sand Sand is the primary substance used in the construction of roads, bridges, high-speed trains and even land regeneration projects. Stone crush Crushed stone is used for concrete aggregate, f
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Fractions Look at the circle. It is divided into 2 equal parts. 1 part out of 2 is coloured of the circle. \(1 \over 2\) of the circle is coloured. The circle is divided in
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The workmen and their tools A mason building a wall with a ‘kandy’ &nbs
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More about Fractions Look at the circle. What fraction of the circle is coloured?
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More about Fractions Look at the circle. What fraction of the circle is coloured?
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Geometry A branch of mathematics that deals with points, lines, angles, surfaces, and solids. Point A point is defined as a location in any space and is represented by a dot (.). It does not
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A few famous buildings of India India Gate &n
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Vertex of shapes The point where 2 sides join is called a vertex A triangle has 3 vertices. A rectangle has 4 vertices. A circle has 0 vertex. A square has 4 vertices.
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Shapes Plane shapes Plane shapes are also called 2-dimensional figures as they have only two dimensions-- length and breadth.
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Shapes Solid shapes Solid shapes are also called 3-dimensional figures as they have three dimension-- length, breadth and height Cuboid: A cuboid has 6 faces, 12 edges and 8 v
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Rolling and sliding Solids with curved surface roll down from a slopping surface. Solids with plane surface slide down from a slopping surface.
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Sky Stars When we see a clear night sky, we observe many stars shining brightly. Stars are very far away from us. Most stars are so far away that we cannot see them at all. Sun The sun is th
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Time A clock tells us the time. It has a minute hand and an hour hand. The longer hand is the minute hand. It shows us the minutes. The shorter hand is the hour hand. It shows us the hours. When th
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Moon The moon is the earth’s only natural satellite. It is our closest neighbour. It is much smaller in size than our earth. The moon does not have its own light. It reflects the light of the s
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Knowing about clock Look at this clock. The minute hand is at 12 and the hour hand is at 3. The minute hand wants to move from 12 to 1. It will need to count 60 seconds to complete 1 m
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Reading clock Look at this clock. The hour hand is at 3. We write 3 on the left side. 3 : The minute hand is at 2. This means it is 10 minutes after 3 o'clock. We write
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Days of the week
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Months of the year
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Seasons of the year These are the four season of year Spring begins from March 1, summer begins from June 1, autumn begins from September 1, and winter begins from December 1
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Money We use money every day in our lives. We buy things using coins and notes. Here are some of the coins and notes we use Coins and Notes
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Combination of Coins and Notes 1.Sara has a Rs. 10 note and two Rs. 5 coins. How much money does she have? Sara has Rs. 20 in total 2. Henry has a Rs. 20 note and two Rs. 2 coins. How muc
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Means Of Transportation Introduction We travel from one place to another. Any vehicle which we use for travelling is known as means of transport. With the advancement in science, better and quicke
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Addition and Subtraction of Money Addition of Money To add two or more amounts, we simply write Rs and P in their respective columns and then add the amounts as ordinary numbers Example: L
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Land Transport All vehicles which travel on land are called land transport. Example bikes, cars, buses, and vans. Trains and metros are the best examples of track transport. &nbs
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Water Transport For water transport, earlier we had boats which we used to paddle. But now we have motor boats and they move very fast. Do you know that a submarine travels under water and a hovercra
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Measurement of length Length Length is a measure of how long an object is. Different lengths are measured in different units. In our daily lives, we measure the lengths of many different item
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Air Transport Aeroplanes and helicopters are the fastest means of transport. They are means of air transport. Astronauts use spacecraft to travel in space.
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Measurement of Capacity Capacity is the amount of any liquid that a container can hold. For example: The capacity of a glass is the amount of water that the glass can hold. Standard unit of c
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Measurement of weight Some things are heavier than other things. We measure the weight of things to know how heavy or light they are. Standard unit of weight is kilogram. Hence, Johny is 2 m
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Data Data is a set of information or facts. It is used to find out things or to make decisions. Getting information from various sources and noting them is called data collection. For example
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Representation of Data Data can be represented in many ways like by using tick marks, blocks etc Using Tick Marks Suppose your table A looks like this Then using tick marks, table B wi
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Means Of Communication Introduction We love and need to keep in touch with our near and dear ones. We do that through different means of communication. Communication means sending or receiving inf
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Different Means of communication In earlier days, we used to write letters, send cards through the post. If we want to post any letter written on a white sheet of paper, we can go to any post office
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A Battle Of Wits The mountain and the squirrel Had a quarrel, And the former called the latter “Little prig”. Bun replied, “You are doubtless very big;
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A Monkey's Tale Once there lived a wise monkey. He was very clever. The other monkeys always listened to him. “My friends,” he would say, “This forest is not a safe place. Fie
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But the monkeys stopped. They did not drink. They waited for their friend. The wise monkey walked round the lake. He saw a strange thing. Marks of feet went down to the water. But no marks came back u
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The Secret Language Of Ants Have you ever seen an ant hill ? Have you ever seen a trail of ants? You might have noticed that ants are usually together. That’s because ants live in groups. The
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It was trying to find its way back home. Then the ant disappeared through a hole in the wall. It was gone for a long time. Some time later, a bunch of ants started coming through the hole in the wall.
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the chemicals and follow the trail. This is how the other ants found the jar of jam. The first ant left the trail of chemicals as it walked back home. This trail showed the other ants the way to the f
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Money Tree Why do they say money grows on trees? I don’t know I admit Her eight-year-old eyes look into my soul. They kind of do though because money is made of paper And paper
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Curious Little Boy I know a curious little boy, Who is always asking “Why?” Why this, why that, why then, why now? Why not, why by-the-by? He wants to know why wood should
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The Power Of Honesty Robert was a great scholar. He is famous. His childhood story of truthfulness is known to all Jaipur with a caravan. He was an intelligent boy and his mother wished him to stud
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Robert was on his way with the caravan. When they were passing through a desert a band of robbers attacked them. They started robbing the money and precious belongings of the travellers. A robber also
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Force And Machines What is Force? Pushing and pulling is a part of our daily life. A hawker pushes his cart to move it from place to place (Figure 7.1). A horse pulls
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Effects of Force 1. Force and Change in Motion Motion is important to our lives and it affects so many things that we do. Motion is the change in position of an object. We have already seen that the
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Distance and Speed Mr. Saleem and Mr. Kareem started their journey from Lahore to Islamabad (400 km). Mr. Saleem boards a train from Lahore. He travels for 4 hours and reaches Islamabad. On the other
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Simple Machines A thing that helps us to do something faster or easier is called simple machine. Simple machines are the lever, the pulley, the inclined plane and the wheel and axle. We shall learn a
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Introduction To Sound Sound We hear different sounds in our surroundings. For example, we hear chirping of birds, car horns and sounds of rickshaws. We listen to the teacher in the classroom. We e
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How is Sound Produced Sound is Produced by Vibrating Objects Sound is produced by vibrating objects. For example, in a drum, skin vibrates to produce sound. In a guitar, strings vibrate to produce so
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Intensity of Sound Sounds of drum, rickshaw, trains whistle, donkey, etc. are very a loud. On the other hand, the sounds of chirping of birds, rustling of laves, ticking of clocks are soft. The loudn
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Medium for Sound to Travel Does the sound need a material medium to travel around? Most of the sounds that we hear reach us by travelling through air. Air is a medium through which sound can travel.
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Noise We feel pleasure to hear music or chirping of birds in the garden (Figure 8.5). Such sounds are called pleasant or musical sounds. There are some other sounds which we do not like to hear; such
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Measures to Reduce Noise Pollution Excessive noise that may harm human health is called noise pollution. There are laws to reduce noise pollution but due to lack of awareness, people do not care abou
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Electricity And Magnetism Everyone is familiar with the word ‘electricity’. It is used to light up our bulbs, tubes and energy savers. It also provides power to refrigerator, washing ma
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Simple Circuit To make use of electricity we have to set up an arrangement through which current can pass. This arrangement is called an electric circuit. Thus, an electric circuit is a closed path t
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Use of a Switch To open and close the path of current easily and safely, we use a switch. These are the switches which make it possible for us to OFF and ON our household electrical appliances safely
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Magnets Surely, you have seen or played with a magnet. It is a piece of material which can attract iron objects like nails, clips and common pins. Some stones also attract iron pieces. These stones a
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Magnetic and Non-Magnetic Materials We know that a magnet pulls some objects. Does a magnet pull objects made up of all kinds of materials? Let us perform an activity to distinguish the objects which
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Movements Of The Earth Shape of the Earth Ancient people believed that the Earth was flat. Therefore, the ships reaching the far ends would fall down and would not come back. In 1519, a Portuguese
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Spin of Earth — Days and Nights It was the old belief that the Earth was stationary while the Sun and the Moon were revolving around it. The occurrence of days and nights was due to their mot
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Revolution of the Earth - The Year When a body is circling around another body, it is said that the first body is revolving around the other body. One complete round trip of a body around another b
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Soil Introduction Soil is the mixture of rock debris and organic materials which develop on the earth’s surface. The major factors affecting the formation of soil are relief, parent material
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Soil Soil is one of the most important natural resources. It provides anchorage to the plants and supplies water and nutrients. It is the home for many organisms. Soil is essential for agriculture.
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Types of soil As you know, weathering of rocks produces small particles of various materials. These include sand and clay. The relative amount of sand and clay depends upon the rock from which the pa
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Water Introduction Water is so important for life that we can not imagine life without it. The evolution of life itself took place in the water. In the evolution of all kinds of life, water has pl
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Need for water Water is needed for three main purposes : domestic purposes, agricultural purposes and industrial purposes. At home, we need water for drinking, washing, cleaning, cooking etc. In agri
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Sources of irrigation Sources of Irrigation Irrigation is an important need. For this, a very large amount of water is needed. To water the crops, there are used different means, the important ones
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Machine Era Introduction Tools and machines are like additional hands that aid us in performing tasks quickly and effectively. From the alarm clock that wakes us up in the morning to the televis
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Tanks and Ponds : Wells cannot be dug where the earth is hard and rocky, like in the Deccan Plateau. In such places, rainwater is stored in tanks and ponds for irrigation and other purposes. A tank
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Industrial Revolution In the progress of civilization, man developed knowledge. To preserve it, he taught it to his children who, in turn, further developed this knowledge. This was how knowledge f
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Steam Engine Handcarts and animal-drawn carts were used until the first half of the eighteenth century. Different types of wheels were being made to fit different types of carts being made. Speed h
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Mass Production The steam engine now made it easy to automate machinery. This meant that the tools which had to be operated by hand could now run on steam. It aided in mass industrial production to
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Innovations In Medicine Introduction Every person needs medicine at one time or the other; for example, when you hurt your foot or when you fall ill. When illness is slight, your mother first trie
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Rivers and Canals: A canal is an artificial channel constructed to convey water from rivers, reservoirs, etc. for several purposes like power generation, navigation, irrigation, etc There are a lar
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Medical Instruments Clinical Thermometer In many illnesses, like an infection, the body temperature goes up. When a doctor feels you warm, he at first measures your body temperature. For t
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Dams A dam is a barrier that stops the flow of water and results in the creation of a reservoir. Dams are mainly built in order to produce electricity by using water. This form of electricity is know
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Microscope The microscope is an important tool found in school laboratories. By placing a small object like a paper pin under its lens, you can magnify and view it clearly. Even tiny particle
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Prevention and Cure Prevention is better than cure, yet a person can fall ill suddenly, which requires cure. Let’s talk about it. Medicines and Antibiotics Medical science has been at w
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Vaccination When a disease has broken out, a treatment becomes necessary. How good it would be if it could be prevented altogether. The scientists have discovered a method to prevent certain diseas
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Basic Health Care Diseases cause various problems. Their cures are time-consuming, painful and expensive. Therefore, prevention remains the best option. There are some simple rules to stay healthy:
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Introduction These are the historic words of Jawaharlal Nehru, the first Prime Minister of India, in 1947 when India gained freedom : “At the stroke of midnight hour when the world sleeps, Indi
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Life in Southern Plateaus of India Introduction The Southern Plateau is located in the southern part of India, stretching from the north to Kanyakumari, the southernmost tip of the country. It is
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The Year 1919 The year of 1919 witnessed the events which made the Indians bitter against the British for all times to come. Montagu-Chelmsford Reforms: The British government passed the Governme
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Jallianwala Bagh Massacre: When people in Punjab protested against the Rowlatt Act, the government arrested two leaders on 10 April, 1919. They were Satya Pal and Dr. Saifuddin Kitchlew. People decid
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Mahatma Gandhi Gandhiji worked as a lawyer in South Africa for 21 years, where he fought for the rights of the blacks. He returned to India in 1915 and was introduced to politics by Gopal Krishna Gok
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Satyagraha and Non-cooperation Movement The British exploited the Indians, so a majority of our countrymen were poor and illiterate. It was not possible for them to give up their livelihood and join
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Emergence of New Leaders During the freedom struggle, many new leaders emerged and contributed significantly to the movement. These leaders included Dr. Rajendra Prasad, Sardar Vallabhbhai Patel, M
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Chhattisgarh Chhattisgarh is located in the basin of the Mahanadi River in the region of Chotanagpur Plateau. The tribal people have a large population here, the important of them being Maria, Muri
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Revolutionary Movement After the Non-cooperation Movement was called off, the freedom movement stalled, and people became impatient for independence. Some decided to take matters into their own hands
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Odisha Odisha has both coastal plains and plateaus. The Mahanadi River has formed a fertile delta here. It receives a lot of rain. It is rich in forests and wildlife. Elephants, bison and panthers
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Maharashtra Maharashtra comprises plateau with a narrow strip of coastal plain. This state has achieved industrial development to a significant level. It is an important centre of textile industrie
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Simon Commission In 1927, the British government appointed a commission, called Simon Commission. It was to study the constitutional reforms. It had only British members, and no Indian representative
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Telangana Located entirely in the Deccan Plateau, Telangana was carved out of the state of Andhra Pradesh on 2 June, 2014. With Hyderabad as its capital, this is the 29th state of India. Its major
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Andhra Pradesh Andhra Pradesh has both plain and plateau. The state of Telangana has been carved out of it. The inner area of Andhra Pradesh is a plateau while its coastal area is plain. Two chief
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Civil Disobedience Movement To pressure the British government, Gandhiji launched the Civil Disobedience Movement in 1930. People were appealed not to obey the British orders. They also asked people
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Karnataka Located on the Western Ghats, Karnataka comprises both plain and plateau. The Krishna, Tungabhadra and Kaveri are important rivers. Both tanks and canals are used for irrigation. There ar
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Government of India Act of 1935 The British first tried to suppress the movement by putting people behind bars; but when the situation remained very grave, they tried to pacify people. In 1935, Gandh
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Quit India Movement On 8 August, 1942, the Congress passed the Quit India Resolution. With this, Gandhiji launched the Quit India Movement. He gave the slogan : Do or die. In no time, the movement sp
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Tamil Nadu Tamil Nadu is bounded by the Bay of Bengal to the east and the Indian Ocean to the south. It has both hills and coastal plains. Kanyakumari, the southernmost point of mainland India, is
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Indian National Army Subhash Chandra Bose, popularly called Netaji, has played a very important role in the freedom struggle. He did not agree with Gandhiji on several points. When the British declar
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India Embraces Freedom The British won the Second World War, but the Indians were now motivated against them. They were ruling India with the help of the Indian soldiers. At first, the Navy revolte
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Life in Western Desert of India Introduction : Rajasthan Jaipur, also known as the Pink City, is the capital of Rajasthan. Harsh living conditions due to sand dunes and scarce water are found here
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Introduction Rise of Nationalism During the First War of Independence in 1857, the Indians had seen the merciless face of the British. The British had indiscriminately killed people, burnt down villa
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Formation of Political Organisations The British government was little interested in the Indians’ welfare. The Indians felt that their voice was not being heard by the British government. Th
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Extremist Phase When the British refused to listen to the demands, some leaders believed in demanding their rights more forcefully, and they were known as extremist leaders. They had faith in the s
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Swadeshi and Boycott Movements To make the British hear, the Swadeshi and Boycott movement was started. People started to boycott the British goods and promoted the Indian goods. The British clo
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Morley-Minto Reforms To pacify the people, the government decided to give them some concessions. They passed a law, popularly called Minto-Morley Reforms. Under it, the Indians were given some seats
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Nationalist Movement Outside India The Indians struggled not only in India but also abroad. The Indians living in other countries started movements for freedom there. Madam Cama went to Geneva and st
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First World War In 1914, the First World War began, and the British sent many Indian soldiers to fight in it. Although India was not involved in the war, its leaders demanded freedom in recognition o
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Humanitarians Introduction There have been many outstanding individuals whose sharp observation, intelligence, original ideas, and labour of passion have laid the groundwork for the better world w
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Mother Teresa (1910 AD - 1997 AD) Agnes Gonxha Bejaxhia, popularly known as Mother Teresa, was born in Yugoslavia in 1910. When she became a nun, she arrived in India in 1929 as a teacher and taugh
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Life in Northern Mountains of India Introduction The northern mountains span across various Indian states, including Himachal Pradesh, Uttarakhand, northern West Bengal, Sikkim, Arunachal Pradesh,
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Ladakh Ladakh, established in 2019, is a union territory with its capital in Leh. It is situated to the north of Himachal Pradesh and is known for its high mountains and sparse population. The regi
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Abraham Lincoln (1809 AD - 1865 AD) Abraham Lincoln was born in a poor family in 1809 in Kentucky (USA). He was very honest, so he was called Honest Abe. One day, in his childhood, he cut down ma
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Himachal Pradesh In this state with charming beauty, there are many valleys and hill stations. It is well-known for its hill stations which include Shimla, Kullu, Manali, Dalhousie and Dharamshala.
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Martin Luther King Jr. (1929 AD - 1968 AD) Martin Luther Some people think that the people with a dark skin are inferior. Martin Luther King Jr. suffered with this kind of discrimination, so he ra
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Uttarakhand The hilly state of Uttarakhand has its capital at Dehradun. It is well-known for its hill stations, such as Mussoorie, Dehradun, Almora, Nainital etc. A large number of people visit its
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Nelson Mandela (1918 AD - 2013 AD) Nelson Mandela was a black man, so he suffered discrimination at the hands of the Whites, so he decided to raise his voice. He was born on 18 July, 1918 in Sout
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Sikkim The capital of the scenic state of Sikkim is Gangtok. Mt. Kunchenjunga, the third highest peak in the world, is located in this state. The people of Sikkim are Lepchas, Bhutias and Nepalis.
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Indian Governance A government has three main functions : 1. It makes laws, that is, it makes rules. 2. It enforces laws, that is, it makes arrangements so that the rules can be put into prac
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North West Bengal The northern part of West Bengal comprises mainly of hills, with the famous town of Darjeeling serving as a prominent hill station. Tea plantation is the primary occupation here,
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Making Laws Central Government The Parliament makes laws for the whole country. The Parliament comprises two houses : the Lok Sabha and the Rajya Sabha. A bill has to be passed by both these hou
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North-Eastern States In the north-east of India are located seven states, known as Seven Sisters. Five of these are located in hills, so we shall study them in this lesson. The north-eastern states i
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Enforcing Laws The laws are like rules. They have to be put into practice. This function is done by the Council of Ministers which comprises the Prime Minister of India and some ministers. Different
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United Nations Introduction Soldiers make great sacrifices to ensure our safety and happiness, but their deaths bring immense suffering to their families. This suffering could be avoided if there
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Nagaland Kohima is the capital of this state, primarily inhabited by the Naga tribe, who are skilled hunters and farmers. They are also talented craftsmen and create various items from bamboo, cane,
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Formation of the United Nations Wars have often been fought in the world, causing untold suffering to the people. Some wars have been very terrible, one such war was the First World War (1914-18). In
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The UN functions through its six main organs : • General Assembly • Security Council • Economic and Social Council • Trusteeship Council • International Court o
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The aim of forming the Trusteeship Council was to help the nations and territories which were then being ruled by the colonial powers. It had been assigned eleven of them as trusts. All these trusts h
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United Nations Educational, Scientific and Cultural Organisation (UNESCO) The UNESCO is headquartered in Paris (France) and aims to promote education, scientific knowledge, and preservation of ancien
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India and UN India is a peace-loving country which maintains cordial relations with almost all countries of the world. To spread the message of peace, it has become a member of several international
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Universal Declaration of Human Rights By virtue of being a human, every person in the world should be given certain basic rights. These rights are called human rights. They help a person to lead a de
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Rights And Duties Our Rights We live in a democracy. The Constitution of India is our supreme law. It has given us some basic rights called Fundamental Rights. Nobody has authority to violate thes
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Our Duties The Constitution of India assigns us some duties also, called Fundamental Duties. We must follow them. These are: 1. We must defend our country by doing national service. 2. We mus
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Means of Transport Introduction Transports are incredibly important to us, and it’s hard to imagine life without them. We rely on them not only for travel but also for getting things we need
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1. Means of Land Transport The transports which run on the land surface are called the means of land transport. They can be divided into two broad types : roadways and railways. Roadways It is ea
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Railways Railway transportation is cheaper than roadways and is an important means of transport in India for both passengers and goods. It’s especially convenient for long journeys and has pl
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2. Means of Water Transport Long ago, people discovered that wood can float on water. This led to the creation of rafts and boats. These boats were used for trade between faraway places. When the s
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3. Means of Air Transport The means of air transport are the latest. They brought to reality man’s dream to fly like birds. The first successful aeroplane was built in 1903 by two American brot
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Life in Northern Plains of India Introduction The northern plains are highly fertile with abundant water resources, resulting in dense population. The people’s lifestyle varies across differ
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Means of Communication Introduction Effective communication is essential for human existence. Whether communicating with others or oneself, it is through various forms of communication that people e
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Haryana Haryana is a small but rich state. It shares its capital C h a n d i g a r h with Punjab. A g r i c u l t u r e is the chief occupation. Scientific implements are widely used in farming. Th
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Teleprinter A teleprinter is like a typewriter. It is an electro-mechanical machine. Two or more teleprinters are connected through wires. When you type a message on one teleprinter, it is automatica
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Chandigarh Chandigarh is the common capital of both Punjab and Haryana. It is a union territory. It is a well-planned and clean city. People are educated and modern. Punjabi and English are widely
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Delhi Delhi is more like a mini-India because we can find glimpses of people from different states. It is located on both banks of the Yamuna. It is a modern urban city which has emerged as an impo
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Facsimile (Fax) The facsimile or fax is a device to send an exact copy of a written material, text message or photograph to another facsimile machine, connected to it through telephone lines. It take
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Uttar Pradesh Uttar Pradesh is the most populous state in India and has highly fertile land that supports large-scale farming of wheat, sugarcane, pulses, fruits, and vegetables. A number of import
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Radio and Television Invented by Marconi in 1886, the radio is a tool of wireless communication. In it, messages are transmitted through radio waves which are received by the radio in any part of t
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Newspapers, Periodicals and Books A newspaper is generally published daily, though there are some weekly newspapers too. Their main content is news on diverse aspects, such as politics, business, spo
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West Bengal With a fertile land and abundant water resources, the main occupation in West Bengal is agriculture. The important crops grown here include rice and jute. Kolkata, its capital, is calle
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Assam Assam, a part of the Seven Sisters, lies in the Brahmaputra basin. Dispur is its capital. The chief crops grown in this state are rice and jute. Petroleum is also mined here. The important la
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Tripura Tripura is a state in the Seven Sisters region, surrounded by Bangladesh. Its capital is Agartala, and its chief crops are rice, tea, and jute. People work in farming or cottage industries,
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Coastal Plains and Islands Life Introduction : Coastal Plains In the last chapter, we learned about the states with a larger part of the plateau. In this chapter, we will study the states and unio
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Daman and Diu Daman is located on the Gujarat coast and Diu is located off the south-east coast in Gujarat. Earlier it was a part of Goa; but after Goa became a state, it became an independent unio
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Dadra and Nagar Haveli This small union territory, with its capital at Silvassa, is located between the states of Gujarat and Maharashtra. It was liberated from the Portuguese in 1954. Farming is t
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Andrapradesh Located on the Malabar coast, Kerala has plains and the Nilgiri hills. The sea has formed many lagoons or backwaters, which are used for transportation and fishing. On the occasion of
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Islands There are two groups of islands in India : Andaman and Nicobar and Lakshadweep. Andaman and Nicobar Islands Located in the Bay of Bengal, about 1,255 km from Kolkata, these islands form a un
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Understanding fractions Look at the circle. It is divided into 4 equal parts. 1 part out of the 4 is coloured. We say that \(1\over4\)of the circle is coloured. \(1\over 4\)is an exam
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Like and unlike fractions Gary’s mother bought two similar cakes. She cut first cake in 8 equal pieces and took 1 piece out. She took \(1\over 8\)of the first cake She cut
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Leaders of India Introduction From ancient times to the present times, India has been served by a large number of leaders in diverse fields. It is not possible to study them all, so we have chosen
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Scientists India was making a great progress in science in the ancient times. During the medieval times, this progress was shelved because of invaders. In ancient times, many scientists worked to u
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Rulers A ruler impacts the nation and society most effectively. Many of our rulers have left a lasting impression on our life. Ashoka the Great ruled about 2000 years ago. Seeing the terrible destr
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Culture of India Introduction : Religions of India India has diverse religions and is a secular country where everyone is treated equally, irrespective of their religion. Hinduism Hinduism is
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Languages of India India is home to hundreds of languages. The Constitution of India recognises 23 of these. These are: Dresses of India Indian attire varies widely across the country, with pop
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Festivals of India The spirit of India comes alive in its festivals. We can divide festivals into three classes : national festivals, religious festivals and social festivals. National Festivals Th
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Music and Dance of India Two types of music and dance are present: classical and folk. To perform classical music and dance, one requires proper training as it follows specific notes. On the contra
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Painting and Sculpture Several styles of painting and sculpture are practised in India. Painting Painting is quite varied in India. A number of styles of painting have become popular in India, su
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National Goals of India Introduction:National Goals As a nation, we aim to achieve certain goals that will make our country strong, prosperous and happy. The Constitution of India, which is the su
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National Symbols India is our country and we are Indians. This is our identity. This identity is fostered by certain national symbols. These national symbols cultivate in us the spirit of patriotism.
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Comparing like fractions Look at the circle. Mary colours 1 part out of 8. She colours \(1 \over 8\) of the circle. John colours 3 parts out of 8. He colours \(3 \over 8
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Ordering like fractions Joe, Patrick and Mama bought a cake. Joe ate \(1 \over 8\) of the cake, Patrick ate \(5 \over 8\) of it and Mama ate \(2\over 8\) of it. Who ate the mos
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Addition and subtraction of like fractions Example 1: Thoma ate \(1 \over 5\) of a cake. Mary ate \(2 \over5\) of a cake. How much did they eat altogether? Both fractions show that
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Transportation Methods Introduction Transportation is necessary for moving people and goods from one place to another, and it is essential for the development of any region. Modern means of transp
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Roadways In the past, people used bullock carts or horse carts as the means of transportation on the roads. Then came the era of bicycles. Nowadays, we have various vehicles like motorcycles, buses,
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Multiplying a whole number with a fraction Recall that if we multiply any number by 1, we get the same number. 1 × 3 = 3, 1 × 5 = 5 etc Similarly, if we multiply any fraction by 1
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Air ways Airbuses are airplanes that carry large number of passengers. They can carry a passenger load of 300-500 at one time. Other than airplanes, there are helicopters which can carry only two or
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Division of a fraction by a whole number Example 1: Divide \(1\over 2\) by 3 We have to divide \(1\over 2\) by 3 Let’s split \(1\over 2\) into 3 equal groups. Each
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Communication Methods Introduction The means of communication can be rightly called the lifeline of a country. Science and technology have played an important role in the development of several ne
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Means of Mass Communication The means of mass communication are used for communication with a lot of people together. Newspaper brings news to our doorstep daily from around the world. Magazine is a
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Equivalent fractions Look at the circle. It is divided into 2 equal parts. \(1\over 2\)of the circle is coloured. Now look at this circle. It is divided into 4 equal parts
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My Favorite Game Hi I am jack, It was February 12, 2020. I attended Annual Sports Day at my school. I got up at 7 o’clock in the morning. I brushed my teeth. I wore my sports kit. My mother a
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My School I’ve got a brand-new lunch-box. My shoes are shiny and clean. I’ve got a cool, new book-bag And a pencil box that’s green. But I don’t kn
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Comparing unlike fractions Example 1: Which fraction is greater, \(1 \over 2\) or \(4\over 6\) ? \(1\over 2\)and \(4\over 6\)are unlike fractions. To compare them, we will
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King Bruce and the Spider Once upon a time, there lived a king in Scotland whose name was Robert Bruce. He was very brave and wise. The king of England wanted to make Scotland a part of England. So
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The Thirsty Ant's Rescue On a hot summer day, a thirsty ant was looking for water to drink. She searched for water and finally reached a river. She climbed up on a stone to drink the water. She
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Addition and Subtraction of unlike fractions Example 1: What is \(1\over 2\)+ \(1\over 8\)? Recall that same sized or like fractions can simply be added by counting the number of par
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Addition and Subtraction of unlike fractions Example 1: What is \(1\over 2\)+ \(1\over 8\)? Recall that same sized or like fractions can simply be added by counting the number of par
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Addition and Subtraction of unlike fractions Example 1: What is \(1\over 2\)+ \(1\over 8\)? Recall that same sized or like fractions can simply be added by counting the number of par
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Addition and Subtraction of unlike fractions Example 1: What is \(1\over 2\)+ \(1\over 8\)? Recall that same sized or like fractions can simply be added by counting the number of par
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Addition and Subtraction of unlike fractions Example 1: What is \(1\over 2\)+ \(1\over 8\)? Recall that same sized or like fractions can simply be added by counting the number of par
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Addition and Subtraction of unlike fractions Example 1: What is \(1\over 2\)+ \(1\over 8\)? Recall that same sized or like fractions can simply be added by counting the number of par
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Joy of Making a Card Jack and Mary are making a card for their mother’s birthday. Let’s see how they do it. First, they make a list of things they will need: • Paper • Sci
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Seasons of the Year Here we go round the year again, To greet the different seasons, Winter time is time for snow. It’s too cold for plants to grow, Because it i
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Improper fractions and mixed numbers Example 1: Look at the following shapes. In fraction \(7 \over 4\) , numerator is qreater than the denominator, Such fractions are called improper f
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Decimals & Fractions Understanding tenths Example 1: Look at the rectangle below Let’s divide it in 10 equal parts and colour one of them. We have coloured one part out of 10, Th
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Shop and Market Shop is a place where things are sold. We cannot purchase everything from one shop. There are different shops in a market. People can get all the things of their daily use from the
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Understanding hundredths Look at the square lt is divided into 100 equal parts Can you write \(3\over100\) as a decimal Hundredths is smaller than tenths, so we will add anoth
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Adding decimals Rahul colours 0.3 of a circle. Sara colours 0.4 of a circle. How much do they co[1]lour altogether? Addition of decimals is similar to addition of whole numbers. Example
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Subtracting decimals Sara colours 0.7 of a circle. She then erases 0.2 of it. How much circle is left coloured? Subtraction of decimals is similar to subtraction of whole numbers. We will wr
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Measurements Length in metres and centimetres We use metres to measure length of objects. Look ot the metre ruler. lt is 1 metre long Example 1: There are 100 centimetres in 1 metre. 1
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Length in centimetres and millimeters For smaller objects, we use centimetres and millimetres to measure the length. Example 2: Anam wants to measure the length of her pencil. She can use
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Length in metres and kilometers For lengths, much greater than metres, we use kilometres. Kilometre is used to measure distances from one place to another. There are one thousand metres in on
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Transportation We use different kinds of vehicles to move from one place to another. For short distances, bicycle and horse-cart are used. For long distances, big vehicles, e.g., motorcycle,
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Mass and capacity Example 1: Ahmad wants to measure the mass of his pencil The mass of the pencil is 3 grams. We can also write it as 3g Example 2: Sara wants to measure the mass of a soc
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Capacity We use litres and millilitres to measure capacity. Look at this measuring cylinder It measures the capacity in millilitres. The amount of water in it is 800 mL There are 1000 mill
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Addition and subtraction Example 1: Rahul's pencil is 15 cm long, Sara's pencil is 12 cm long. What is the total length of both the pencils? To find total length, we will add both length
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Time Look at the clock. It tells us time It has hours hand, a minutes hand and a seconds hand. The small thick hand is the hours hand. It shows us the hours. The long thick ha
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Good Manners Good manners cost us nothing, but may win almost everything. hey are the skills of making people feel easy and comfortable. We can have better relationships with people we know an
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Other Good Manners : • Always speak softly and politely. • Often use words like “excuse me”. • Always greet everyone with a smile. • Be obedient to your paren
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Plants around us Plants We see many kinds of plants around us. Leaves of different plants are different in shape and size. Some plants are tall, some are small and some are medium size. Tall plant
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Small Plants: Small plants are smaller than trees. Their stems are thinner and weaker. They need lesser space to spread. They are not very tall. Shrubs, herbs, climbers and creepers are small plants.
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Thorny Plants: Some plants have thorns. Animals do not eat such plants. Such plants are called thorny plants. Bunny Ear cactus, Barrel Cactus. Water Plants: Some plants grow in water. They are
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Animals around us Animals We see many kinds of animals around us. Some animals live in water and some on land. Birds fly in the air. Insects live in or above the soil. Some animals eat grass. So
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Wild Animals Some animals wander freely in jungles. They are called wild animals, they cannot be tamed Tiger, lion, fox, bear, deer, etc., are wild animals. You can see some wild animals in zoo. Wild
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Mammals The animals like elephant, monkey, deer, bear, horse, goat, cow, human being, etc are called mammals. Mammals give birth to their babies and feed them with their own milk. Bat is a flying mam
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Reptiles The animals that crawl along with the ground are called reptiles. Lizard, chameleon, snake and tortoise are reptiles. Small animal with sharp teeth like rat and rabbit are called roden
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Objects around us T h e house of my f r i e n d Simon is in front of my house . There is a market near my house. There are many shops in the market. We buy many things from these shops. My school i
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Some objects are big and some are small. Some objects are hard and some are soft. Some objects are heavy and some are light.
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Many objects produce sound. Sounds are produced by different ways. Objects can be seen in light at day time. At night we need light to see the objects.
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Objects made of wood. Objects made of Paper. Objects made of Plastic. Objects made of iron. The same objects can be made by iron, wood and plastic.
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Converting Time Example : Rahul took 1 hour 10 minutes to finish his homework. How many minutes did he spend on his homework? We know that there are 60 minutes in 1 hour 1 hour 10 minutes = 1
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am and pm Rahul and Jack are going to school. It is 9 o' clock. We say It is 9 am. Rahul and Ramu are eating dinner. It is 9 o’ clock again. We say It is 9 pm There are 24 h
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Addition and subtraction of time Example 1: Jack's family left the house at 4:15 am and reached Delhi after 5 hours 20 minutes. What was the time when they reached Delhi? We will add 4 hours
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Conversion There are 7 days in a week. Example 3: Jose's father went to Hyderabad for four weeks. How many days are there in 4 weeks 1 week = 7 days 4 weeks = 7 × 4 = 28 da
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Geometry Line A line is a straight path without thickness. It can be a straight path in any direction. Below are some lines The arrows show that the lines can be extended in any direction
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Horizontal and Vertical lines Look at this line. It goes from side to side or left and right We call such line horizontal line. Look at the picture of the house. There are many vertic
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Parallel and non-parallel lines Look at these two lines They are always at the same distance from each other. We call such lines parallel lines. Parallel lines are the lines that are at s
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Identifying angles When two non-parallel rays meet at a point, an angle is formed Angle is marked with a curved line Two straight rays meet each other at point B. B is the vertex of th
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Measuring and drawing angles We measure angles in degrees (°). There are 90° in a right angle. There are two right angles in a straight line. A straight line is 180°.
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Circle Look at the circle. It has no sides. lt has a centre Centre is a point from which all points on the circle are at the same distance. We can draw a line segment from the ce
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Money We use money every day in our lives. We buy things using coins and notes. Here are some of the coins and notes we use
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Coins and Notes
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Conversion of Money Rule 1: To convert rupees to paise, multiply the rupee amount by 100 Example: Convert the following amounts into paise : (a) ₹ 8 &nbs
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Addition and Subtraction of Money To add or subtract money in rupees and paise, write the amounts in separate columns of rupees and paise by writing the dots. Then, as with whole numbers, simple ad
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Area & Perimeter Perimeter of a Square The perimeter of a shape is the total length of its sides. To find the perimeter of a shape, you need to add up the lengths of all its sides Fo
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Area Of a Square and Rectangle The area of a square can be calculated by multiplying the lengths of its two sides. If the side length of a square is 4 cm, then the area of the square can be
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Finding Perimeter of Irregular Figures We can find the perimeter of an irregular figure by using the given formula: Perimeter of any irregular figure = Sum of the lengths of all the sides
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Data Handling A Bar Graph Sara buys four types of fruits in different quantities. We can read the picture graph by counting the in each column
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We can also show this data on a vertical bar graph. A bar graph uses bars instead of pictures to show data. We can find out how many apples, bananas, oranges and watermelons Sara bough
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We can also represent data on a horizontal bar graph. The bar graph shows number of toys sold by a shopkeeper over four months The number of toys sold every month can be read from graph.
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Line graph Jack has flowers of 4 different colours. The following table shows number of flowers of every colour, Jack has We can also show this data on a line graph. On a line graph, instead
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Addition and Subtraction Addition Addition is an act of combining things together. It is illustrated by the following examples Example 1 There are 6 balls kept on a table. If we put 3 more
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Addition without Carry over Addition of 2-Digit and 1-Digit Numbers. Let us add 15 and 4.
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Addition with Carry over Let us add 18 and 14.
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Earth and Sky Yes, the earth is the planet which we can touch everyday. We live on this planet. It's shape is like an orange. It is covered by layers of air. It is made up of land and water. Wa
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Subtraction Subtraction without Borrowing Subtraction of 2-Digit and 1-Digit Numbers. Let us subtract 15 and 4.
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Subtraction with Borrowing Let us subtract 24 and 18.
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Land Types Mostly, the earth has plain land. Plain land is flat. It may be grassy or sandy like a desert. Desert area is filled with sand. The land of the earth is not plain everywhere. Some parts
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Water Bodies Our drinking water comes mostly from rivers and lakes. The main water bodies are seas and oceans. There are many water plants and animals in these water bodies. Water bodies are very u
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The Sky We see the blue sky far above the earth. During the day, we see the bright sun on sunny days. The sun rises from the east and sets in the west. During the night, we see the moon and many st
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Introduction The things or objects, which we all use in our daily life are made up of different types of materials Examples: Pen, Book, Chair etc.... Material is a substance that is used for makin
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Good and bad conductor of electricity Materials can be classified based on their electrical and thermal conductivity. Conductivity is a measure of how well a material allows the flow of electricity o
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Weather What is weather? The conditions in the air above the earth such as wind, rain or temperature, especially at a particular time over a particular area are called weather. Weather changes fro
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Combustible And Non-Combustible substances: Materials can be classified based on their behavior during combustion, which is the process of burning. Combustion involves a chemical
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Hot Days: Some days of the year are very hot. Sun shines brightly on hot days. People like to sit under the fans or in air conditioners and cooler to keep themselves cool. Some people go to hill stat
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Based on solubilities: Materials can be classified based on their solubility, which refers to the ability of a substance (solvent) to dissolve
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GROUPING OF MATERIALS Materials are classified into groups together on the basis of similarities and differences in their properties. This is done for convenience and to study their properties easi
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Seasons Depending upon weather, We have four seasons. (i) Winter season, (ii) Spring season, (iii) Summer season, (iv) Autumn season. These seasons depend on weather. Spring season is very pleas
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Solids,Liquids And Gases MATTER: Any material which has mass and occupies space is called matter. CHARACTERISTICS OF MATTER : (i) Matter is composed of
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SOLIDS: In solids, the molecules are closely packed, when heated at melting point, it changes its physical state and becomes a liquid. For an instance, W
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Liquids The spaces between the molecules of a liquid are slightly more than that in a solid but they are still very small. Due to comparatively less strong intermolecular forces,
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GASES: The molecules of a gas have the maximum movement (or maximum kinetic energy). Due to this, the gases have the most disorder arrangement of molecules. Because of high kinet
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PLASMA : Plasma is the fourth state of matter. Plasma is an ionised gas, a gas to which sufficient energy is provided to get free electrons from atoms or molecules to allo
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Separation Of Solids-Solid Mixtures SEPERATION OF MIXTURES: Mixture is said to be pure when its components are known and they are put together in a desired quantity.We nee
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Magnetic separation: This process is based on the magnetic property of one of the component. Ex: Mixture of iron ore and sulphur. Iron ore is attracted by magnet and sulphur is
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Sublimation: This process is based on the ability of one component to sublime. Ex: Mixture of iodine and sand. On heating iodine sublimes leaving behind sand. The vapours on cooling gives solid io
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Separation Of Solids-Liquid Mixtures Sedimentation: The process of settling down of a heavier and insoluble components from a mixture in a liquid is called sedimentation. Ex: 1. Sedimentation of
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Evaporation: When a liquid changes into gaseous state on gentle heating, such that liquid does not boil, the process is called evaporation. The process of evaporation is employed t
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Air Around Us-Introduction Introduction We have learnt that all living things requ
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IS AIR PRESENT EVERYWHERE AROUND US? Close your fist — what do you have in it? Nothing? Try the following activity to find out. Activity Take an empty open bottle.
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WHAT IS AIR MADE UP OF? Until the eighteenth century, people thought that air was just one substance. Experiments have proved that it is really not so. Air is a mixture of many g
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Multiplication Introduction Multiplication is repeated addition. Let us understand the concept of multiplication. How many oranges are there altogether? There are 3 gr
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Carbon dioxide In a closed room, if there is some material that is burning, you may have felt suffocation. This is due to excess of carbon dioxide that may be ac
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HOW DOES OXYGEN BECOME AVAILABLE TO ANIMALS AND PLANTS LIVING IN WATER AND SOIL? Activity Take some water in a glass or metal container. Heat it slowly on a tripod stand.
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Multiplication Tables Multiplication Table of 2
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Multiplication Table of 3
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Multiplication Table of 4
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Multiplication Properties The Zero Property: When you multiply any number by 0, the answer is always 0. For example, 3 x 0 = 0 and 0 x 6 = 0. The Identity Property: When you multiply any number by
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Multiplication Word problems 1. Tommy has 3 bags with 5 toys in each bag. How many toys does he have in total? Tommy has 15 toys in total..
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Shapes And Patterns Introduction Basic shapes are simple shapes that can not be broken down into simpler shapes by general conventions, examples include square, circle, triangle, etc. Compound sh
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Plane Shapes
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Solid Shapes Solid shapes are different from flat shapes. These shapes have height or depth. Description about solid shapes: This is a cone. A cone has 1 flat face and a curved face. Cone h
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Patterns We see different patterns in the different things in our day-to-day life. Example: Clothes, Pavement, Gate, Jewellery We can see patterns in some the historical monuments. Colosse
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Time and Days Introduction Time: The passing of minutes, days, weeks, years, and centuries. There are two hands in a clock. The big hand is the minute hand. The small hand is the ho
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Analog Clock It is a timekeeping device that has numbers around the edge and hands that rotate around to indicate the time. Let’s look at the time on a analog clock.
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Digital Clock Digital clocks use not hands to show the time. The hours are on the left and the minutes on the right. Let’s look at the time on a digital clock.
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Year, Months, Days. A week has seven days. ‘‘Sunday is the first and Saturday is the last day of the week’’ 30 or 31 days make a month. 12 months make a year. A year
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Money Introduction Something (such as coins or bills) used to buy goods and services and to pay people for their work. We can buy toys, fruits, vegetables etc. with money. Let’s discuss o
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The representation of money in terms of splitting.
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Measurements BIG AND SMALL Match similar objects with each other. Encircle the smaller balls. Encircle the bigger leaves.
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Long and Short Encircle the longer object. Encircle the shorter object.
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Tall and Short Encircle the shorter object. Encircle the Taller object.
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Light and Heavy Encircle the heavier side. Encircle the lighter side.
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Far and Near Encircle the car which is near the boy. Encircle the dog which is far from the house.
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Inside and Outside
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Over and Under Right and Left The red car is going left. The green car is going right. Draw a line from the strawberries to the basket in the right hand. Draw a line from the flowers to th
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Measuring Lengths Sometimes the question may be arise that how long an object is. For this, we measure the length of the object. For example: Jack’s stick box is (5) pencils lon
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Data Handling Data Data is a collection of information. It is used to find out things or to make decisions. Look at this vegetable seller: How many vegetables of each kind are there? The nu
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Invertor And Inventions About ancient times Making something new, which did not exist before is called invention. One who invents something new is called an inventor. In the ancient times, people
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Division Review : Simple division Lily has 6 balls. She puts them equally into 2 boxes. 6 ÷ 2 = 3 6 divided by 2 is equal to 3. There are 3 balls in each box. Now, Li
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Inventions & Inventors Aeroplane Before the invention of the aeroplane people used to travel by buses, trains and ships. It took several days to travel from one city to another. After the inve
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Division of a 2-Digit Number by a 1-Digit Number Example: Divide 48 by 2. 48 ÷ 2 Solution: Step 1 Write the division sum like this Step 2 Start from the lef
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Fax Machine The first fax machine was invented by Scottish mechanic and inventor Alexander Bain. In 1843. Fax machine sends written messages and photographs within a few minutes from one place to ano
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Telephones: have changed a lot over the years. Before the first mobile phones (or cell phones) were invented over thirty years ago, nearly everyone used phones connected to telephone lines. These lin
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Division of a 4-Digit Number by a 1-Digit Number Division without Remainder Example: Divide 6715 by 5. Solution: Step 1: Arrange the numbers for division. Step 2: Divide 6 by 5. 5 &t
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Division of a 4-Digit Number by a 2-Digit Number Division without Remainder Example: Divide 5083 by 23. Solution: Step 1: Arrange the numbers for division. Step 2: Divide 5 by 23. But
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Division problems in daily life There are 28 biscuits. The biscuits are put equally in 7 boxes. How many biscuits are put in each box? 28 ÷ 7 = ? There are 4 biscuits in each box.
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Properties of Division Property – 1 When 0 is divided by any number, the quotient is 0. For example: 0 ÷ 15 = 0 Property – 2 Division by 0 is meaningless.
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Measurement - Length, Mass, Capacity Measuring Length Length Length is a measure of how long an object is. Different lengths are measured in different units. Units of Measuring Len
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Metro Cities Of India Delhi Delhi is the capital of India. It was one of the seven Union Territories of India, now known as the National Capital Territory. Delhi is situated on the banks of the ri
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Mumbai Earlier Mumbai was known as Bombay. Mumbai is the capital of Maharashtra. It is situated on the west coast of India facing the Arabian Sea. Food Vada Pav When it comes to Mum[1]bai street fo
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Measuring Mass Weight is an object’s property that tells us how heavy it is Units of Measuring Weight 1. The standard unit of measuring weight is ‘kilogram’ denoted by &ls
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Kolkata Kolkata was earlier known as Calcutta. It is the capital of West Bengal. It is situated on the east bank of river Hooghly. It is one of the four metro cities of India. Food Rasgulla and oth
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Chennai Chennai is the capital of Tamil Nadu. Tamil Nadu is one of the southern states of India. The old name of Chennai is Madras. Chennai is the fourth largest city of India. It is located along th
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Measuring Capacity Capacity is the amount that a container or vessel can hold. To measure different sizes, different units are used. Units of Measuring Capacity Litre: The standard unit of
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Our Country India Government Every person of a country is the citizen of that country. The government of the country looks after the people like the guardian of a family. The government makes the
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The State Government India’s population is ranked second among the other populous countries of the world. The existing population of our country is over 130 crore. It is difficult to look after
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State
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The Union Territories of India Because recently The state of Jammu and Kashmir has been converted into Union territories.
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Fractions Look at the circle. It is divided into 2 equal parts. 1 part out of 2 is coloured. \(1\over 2\)of the circle is coloured. The circle is divided into 4 equal pa
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Comparing Fractions Example:
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Addition of Fractions John’s mother makes a pizza. She divides the pizza into 6 parts. Sara eats \(1 \over 6\) of pizza John eats \
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Equivalent Fractions Example: John makes a circle. He divides the circle into 4 parts. He colours \(1 \over 4\) of the circle. Sara makes a circle She divides the circle int
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Our Houses Houses We need a house to live in. Our house protects us from heat, cold, storm and rain. It also protects us from animals and thieves. We see different types of houses around us. The t
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Multi-storey building: A multi-storey bulding is also a pakka house. It has many floors. Many families can live at different floors. Special Houses People who roam ar
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Time A clock tells us the time. It has a minute hand and an hour hand. The longer hand is the minute hand. It shows us the minutes. The shorter hand is the hour hand. It shows us the h
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Healthy and happy family A Good House A good house should have all the things we need to make ourselves safe and comfortable. A good house should have the following features: 1. It should be well-ve
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Time in daily life (am/pm) Joseph and Sara are at the school. The time is 8 am Joseph and Sara are eating dinner. The time is 8 pm Read the sentence and encircle the right opt
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A Clean House We must keep our house clean. Some insects like mosquito, housefly and cockroach spread diseases and make us sick. We can remove them by cleaning our house regularly. To keep our h
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Time Addition Example: Look at the time. It is 3:00. We say it is 3 o’clock. What will be the time after 2 hours? It will be 5 o’clock after 2 hours
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Clothes We need clothes to cover our body and to keep us warm in winter. Clothes also protect us from the heat of the sun, cold, rain, and insect bites. Early man used the skin of animals to cover th
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Time subtraction Look at the time. It is 10 o’clock What will be the time 2 hours before? Look at the time. It is 8 o’clock.
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Clothes that suit the Weather We wear clothes made of different materials according to the weather of the place we live in. In summer, we usually wear light-coloured clothes made from cotton or linen
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Geometry Review: Point A point is defined as a location in any space and is represented by a dot (.). It does not have any length, height, shape, or size Line A line is a one-dimensional f
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Ray We know about sun-rays. A sun-ray starts from the sun and goes on a direc[1]tion up to endless space. Similarly a geometrical ray is considered a special kind of line which starts from a fixed
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Horizontal Line The lines drawn horizontally are called horizontal lines Vertical Line The lines drawn vertically are called vertical lines Slanting Line The lines drawn in a slanti
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Measuring line segment If you are given a line segment of any length, then you can measure it with the help of ruler. Suppose we have to measure the length of line segment \(\overline{AB}\) give
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Plane shapes Triangle A triangle has three sides and three corners. The triangle has no diagonal. The lengths of the sides of a triangle may or may not be the same.
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Perimeter The perimeter of a figure is the total distance around all sides of the figures. Look at this square. Each side is 3 cm long. What is the total length of the square? 3cm +
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Plants Life Parts of a plant and their uses A plant has two main parts: 1. Root 2. Shoot The part above the ground is called the shoot. It consists of the stem, leaves, buds, flowers and fruits
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Data Handling Data Pictograph is referred as the representation of data in picture form. In ancient time pictograph was the method for writing the information. Numbers were also represented in p
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Roots Root is the part of the plant that usually grows below the ground. There are two main types of roots, taproots and fibrous roots. Taproots It consists of a main, thick root from which small
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Tally marks Tally marks are defined in the unary numeral system. It is a form of numeral used for counting. The general way of writing tally marks is as a group or set of five lines. The first four
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Stem The stem is the main part of the shoot. The stem can be. Strong stems The trunk of the trees are thick and strong. It holds the tree straight and upright. We
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Leaf Most plants have green leaves and it grows on the branches of a plant. They differ in size and shape. The green color of a leaf is due to chlorophyll. The flat part of a leaf is called the leaf
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Pictographs A pictograph is a graph that uses pictures or symbols to represent numbers. It is known as the base point of all graphs James buys four types of fruits. He uses a pictu
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Flower The most beautiful part of a plant is the flower. We see flowers like rose, jasmine and lotus. Flowers are of many colors, shapes and sizes. Most of the flowers look very beautiful. Many flowe
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Birds Bird Birds are beautiful animals that can fly. Their body is divided into three parts –head, trunk and a tail. They have two pairs of limbs – the legs and the wings. Birds have l
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Let us now learn about the beaks of birds. Beaks A bird uses its beak to catch and eat food. Different birds have different kinds of beaks depending upon the food they eat. Birds such as sparrow a
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Feet and Claws Birds have two feet usually with four toes on each. They use their feet to walk and hop around, as well as to catch and hold food. Flesh-eating birds such as eagle and vulture have ve
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How birds fly Birds fly with the help of wings. Wings are joined to the body with strong muscles that help them to move. These muscles help the birds to move its wings. To fly, a bird flaps its
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Feather A bird’s body and wings are covered with many feathers. There are three kinds of feathers, 1. Body feathers 2. Down feathers 3. Flight feathers 1. Body feathers cover a bird&rsqu
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Nest Bird’s build nests using leaves, straws, twigs, wool, cotton and thread. Birds take care to build their nests in places safe from enemies and bad weather. We can see birds’ nests on
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Our Body Human body Human body is like a wonderful machine. It is unique and the most amazing machine in the world. It is capable of doing many things that no other machine can do. Human beings ar
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External Organ The external organs of our body are eyes, ears, nose, tongue and skin. We can see these organs. These external organs are our sense organs. Sense organs are important parts of our body
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Body Parts
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Sense Organs Every human being has similar body parts. Yet, we look different from one another. Why? The shape and size of the body parts differ from person to person. This makes us look different
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Internal Organs We have a number of internal organs. We cannot see our internal organs. However, these organs help the body to function smoothly and keep us healthy and alive. The internal organs ar
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How should we take care of the sense organs? We should look after and take proper care of our sense organs. We must keep our sense organs clean and protect them from damage. The eyes: (i) Eyes ar
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Living and Non-Living Things We see many living and non-living things around us. We see men, women, children, animals, plants, birds, insects, bicycles, houses, stones, roads, benches, the Su
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Man-made things There are many things which are made by man. They are called man-made things. Man has made things to satisfy his needs. Man needs shelter, so he makes homes. Man also needs clothes,
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Living things and non-living things We know, natural things include living things and some non-living things. Things like humans, animals and plants that have life are known as living things. Thing
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Living things breathe air to live. Practice the activity to check this on your own. 1. We can press our nostrils between our thumb and finger now we are unable to breathe and we feel uncomfortable.
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Living things need food and water to survive. If any such creatures do not get food for a very long time, they will die since; we know no living things can survive without food and water. Food and
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A Thief In the Market Red, green, blue, yellow, orange, purple - there were colours everywhere Alice looked. This was her first trip to the local market with her mother. She had been allowed to go
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“Get twenty rupees off if you buy two kilograms of tomatoes!” screamed another. Besides food, Alice also saw shoes, jewelry and clothes being sold. She loved how a shopkeeper’s smile
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Alice returned the bag to its owner. “I have never felt more proud of you, my daughter”, said her mother. Everyone present at the market cheered for the little girl and called her a he
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The Magic Pencil Looking left and right, Sara was unable to find a single tree to protect her from the hot summer sun. She missed the days when her community was surrounded by greenery. She used to
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A team of developers had chosen Sara’s community as the site for a new shopping center. They promoted this idea by telling people about all the fantastic facilities this shopping center would ho
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The seeds would get water from the rain and nutrients from the soil. This would help them grow, and eventually turn into trees. Grabbing the pencil she was using to finish her homework, Sara wondered
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Nature By putting a smile on a crying face A smile blooms on my face too By giving shelter to a tired traveler Tiredness of my mind disappears too. By giving water to a thirsty man Desires o
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Serving others is a noble quality that brings welfare in the society So we should share what we have with others As it brings out the best in us. Helping others is a great feeling Believe m
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Shelly the Little Snail Shelly is a little snail. She is called Shelly because her home is a shell. Shelly slides very slowly along the ground. One day she slid a long way...about 100 metres. S
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Respect for Elders On the way to School Joseph and Aaron are going to school. They pass through a muddy patch. They try to go from a sidewalk. Suddenly, they see an old woman crossing the muddy r
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Festivals The horse and cattle show Benjamin is a ten year old boy who loves animals. Let us see what David saw at the Horse and Cattle Show. Benjamin came to Chennai to stay with his uncle for
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Benjamin loved animals so he was very happy and excited. All the animals had been decorated with flowers and beads. The animals stood in a line and followed their masters’ orders. Just when the
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Solids, Liquids And Gases MATTER: Any material which has mass and occupies space is called matter. CHARACTERISTICS OF MATTER : (i) Matter is composed of tiny parti
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SOLIDS: In solids, the molecules are closely packed, when heated at melting point, it changes its physical state and becomes a liquid. For an instance, When a solid substance is heated, the hea
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Liquids The spaces between the molecules of a liquid are slightly more than that in a solid but they are still very small. Due to comparatively less strong intermolecular forces, the positions of mol
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GASES: The molecules of a gas have the maximum movement (or maximum kinetic energy). Due to this, the gases have the most disorder arrangement of molecules. Because of high kinetic energy and negli
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PLASMA : Plasma is the fourth state of matter. Plasma is an ionised gas, a gas to which sufficient energy is provided to get free electrons from atoms or molecules to allow both the species,
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Symbols And Rules Introduction : In order to represent the elements, instead of using full lengthy names, scientists use abbreviated names. These abbreviated names of the
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Classification Of Matter Matter is defined as something which has some mass and occupies some space. It occurs in three different states based on physical classification. They are solid
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Rules of Assigning Symbols Symbols can be denoted by the single letter, two letters & three letters. The symbols of elements are generally either the first or the first two le
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Properties of different states of matter based on physical classification: The three states of matter exhibit different properties. Their properties can be shown in the form
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Valency And Ions When atoms of two or more elements combine, a molecule of a compound is formed. The capacities of these elements to combine with each other determine the formula of the compound fo
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Modern Definition of Valency : According to the new concepts, Valency can be defind as the number of electrons that are lost or gained or shared with one atom of
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Nuclear Composition of Elements Electronic Configuration of Elements The distribution of electrons in different orbitals is known as Electronic Configuration of Elements
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Valence electrons: The electrons in the outermost shell of an atom are called its valence electrons. Example : The number of valence electron in sodium is one.
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Interconversion of states of matter : The method of changing the matter from one state to another state by altering the conditions of temperature and pressure & back to the original state i
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Radical or Ion : When an atom looses or gains electrons it converts into Radical or Ion. (or) An atom or group of atoms with charge on them is called Radical or ion (ii) Classification of ions: Ions
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Electropositive ions When an atom looses one or more electrons to get stability, The number of electrons lost by an atom of an element is its Positive valency an
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Monovalent electropositive ions When an atom looses one electron or if any Radical or ion has uni positive charge on it then it is known as Monovalent electropositive ion or Unival
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Trivalent electropositive ions When an atom looses three electrons or if any Radical or ion has tripositive charge on it then it is known as Trivalent electropos
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Symbols Of Elements And Rules ELEMENT: The substance which cannot be broken down into simpler substances by physical or chemical means is called as an Element. SYMBOL: The short hand
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Concept of Variable Valency Most elements such as Na, K, Mg, Al, Ca, Ba etc..exhibit a fixed valency in all their compounds, Sometimes the same element may for
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Electronegative Ions : The species which carry negative charge on them (or) The species formed by gain of electrons by an atom are called Electronegative Ions.
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Monovalent negative ions: A radical formed when an atom gains one electron is called monovalent negative ions. llustration 2: If in an element X there are seven electrons present in
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Physical And Chemical Changes Physical and chemical changes: All substances around us undergo changes. In some cases, the changes are small and difficult to defect. In other cases, the changes are
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Bivalent Electronegaive ions A Radical or Ion which is formed by gaining of two electrons is called Bivalent Electronegaive ions Trivalent Electronegaive ions A Radical or Ion which is formed by
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Formula : The symbolic representation of one molecule of a compound representing the number of atoms of various elements present in it is called formula of the co
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Naming chemical compounds from their fromula Usually the elements present in a compound are named in order of symbols appearing in formula. Following rules are applied in a
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Naming of Acids: a) The name of binary acids (acids containing hydrogen and one more element)are given by adding prefix hydro- and suffix-ic to the name of second element. Examples: i) Acids o
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Metals And Non Metals ELEMENTS: Substances which cannot be broken further into any other substances by any physical or chemical means are called Elements. Examples:Hydrogen,Oxygen,Nitrog
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NON-METALS An element is considered as non-metal if it has following characteristics. i)It is non-lustrous i.e. it cannot glow. ii) It is bad conductor of heat and electricity.
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Metalloids Metalloids are the elements which show both metallic and non-metallic properties. Ex:Boron, Silicon, Germanium,Arsenic,Antimony, Selenium ,Tellurium There are 7 metalloids in natur
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SYNTHETIC FIBERS AND PLASTICS A fiber (or fibre) is a slender, elongated, thread-like structure that occurs naturally or can be produced artificially. Fibers are fundamental components us
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Synthetic Fibers: Synthetic fibers are man-made fibers produced through chemical processes using polymers derived from petrochemicals or other chemical sources. Unlike natural fibers, which are obt
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Characteristics of Fibers: Length: Fibers can be short or long, and their length contributes to the properties of the end product. Flexibility: Fibers are often flexible and can be woven or knit
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Some Important synthetic fiber Nylon: Nylon is a synthetic polymer and a type of synthetic fiber that was first developed by a team of researchers led by Wallace H. Carothers at DuPont in the late
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Rayon: Rayon is a versatile and widely used semi-synthetic or regenerated cellulose fiber. Unlike synthetic fibers, which are entirely man-made from petrochemicals, rayon is derived from natu
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Acrylic Acrylic is a synthetic fiber known for its versatility, durability, and a range of applications. It is derived from acrylonitrile, a petrochemical compound, and is considered a synthetic or
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Polyester Polyester is a synthetic polymer made from petroleum-derived chemicals. It is a versatile and widely used synthetic fiber known for its durability, wrinkle resistance, and ease of care. P
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PLASTIC Plastic is a synthetic or semi-synthetic material made from polymers—large molecules composed of repeating structural units called monomers. Plastics are versatile materials known for
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Common Types of Plastics: Polyethylene (PE): Used in packaging (plastic bags, containers), pipes, and various consumer goods. High-density polyethylene (HDPE) and low-density polyethylene (LDPE)
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Types Of Plastics Thermoplastics and thermosetting plastics are two major categories of polymers or plastics, distinguished by their response to heat and the nature of their chemical bonds. The key
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Biodegradable and Non-Biodegradable Plastic Biodegradable Plastics: Biodegradable plastics are designed to break down naturally in the environment through the action of microorganisms, such as bac
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4R Principle - Reduce, Recycle, Reuse And Recover The 4R principle, often applied to waste management, stands for Reduce, Reuse, Recycle, and Recover. It is a guiding framework for minimizing the e
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COMBUSTION, FUELS AND FLAMES What is Combustion? Combustion is a chemical reaction between a fuel and atmospheric oxygen (an oxidizing agent), resulting in the release of heat and the formation of
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Does air is necessary for combustion process? Lets do an activity: To test the necessity of air (specifically, oxygen) for burning, you can perform a simple experiment. Keep in mind that safety pr
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Ignition Temperature It is a crucial factor in understanding the flammability of materials. The ignition temperature, also known as the kindling point, is the minimum temperature at which a substance
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Types of combustion Combustion can occur in various forms, and different types of combustion processes are categorized based on specific characteristics. Here are some common types of combustion:
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Structure Of Flame The structure of a flame is determined by the combustion process occurring within it. Flames can vary in appearance based on factors such as the type of fuel, the availability
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Calorific Value Calorific value, also known as heating value or energy content, is a measure of the amount of energy released during the combustion of a substance. It is typically expressed in term
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COAL AND PETROLEUM Introduction We use different kinds of materials as fuels for various purposes at home.You might have observed or heard about how people us
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What is needed for the process of combustion? • We know that we need a match stick or a lighter to burn a material. • How will you prove that air is
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Exhaustible and Inexhaustible Resources: Now, we have to think about few questions to understand about need and importance of natural resources. • Will the above resources
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Bio-diesel an alternative fuel source: Bio-fuels are one of the major non-conventional energy resources.They are non-toxic and renewable.Bio-diesel is one of the bio-fuel which is an alternative or
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Natural gas Natural gas is found trapped betweenimpervious rocks, sometimes along with petroleum and sometimes witho
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Other uses of coal, petroleum and natural gas: Most of us think petroleum is a source of fuel.
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Formation of coal: The plants in large and dense forests in low lying wetlands got burried under the soil due to the natural processes like floods and earthquake
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Conserving coal and petroleum: Why does the price of petrol go up all the time? In simple terms, the price of any
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Misuse of energy resources and consequences: In our daily life while doing various day to day activities we use many types of energy resources and fuels without giving a thought about the exhaustib
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Harmful effects caused during use of fuels: Most of the harmful effects are due to carelessness of handling petroleum products. For example, crude oil and refi
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How to Identify a Physical Change? Sometimes, identifying and classifying a change as a physical change might seem difficult and seemingly impossible. The following pointers can help you understand w
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What are Chemical Changes? A chemical change is one where there are changes in the chemical properties of the components. Their chemical composition may change and the final product may have differen
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Experiments to Show Chemical Changes: Burning of Magnesium ribbon: When a small piece of a thin strip or ribbon of magnesium cleaned with sandpaper is brought near the flame, then it burns with a bri
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Acids, Bases & Salts-Indicators In this chapter we learn about: 1. Indicators 2. Acids 3. Bases 4. Salts 5. &nb
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INDICATORS For identifying a substance as an acid or a base we make use of certain natural chemical substances which show a change in colour when placed in acid medium, base medium. These chemical
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Acids Substances with sour taste and changing blue litmus to red are called acids. The term acid has been derived from Latin word acidus, which means sour in Latin. Basing on origin, these classified
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Preparation And Properties Of Acids The acids which undergoes complete ionisation when dissolved in water and furnish large concentration of H+ ions are called strong acids. Ex:- &nb
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Preparation of acids 1.From Non metals. Elements such as carbon, sulphur, phosphorous etc. are burnt in oxygen and form their oxides.These Oxides when dissolved in water forms respective aci
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Physical Properties of acids i) All the acids are colourless, though sulphuric acid may be brown at times due to impurities. ii) Acid taste sour. iii) Acid turn blue litmus red
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Uses of Acids a. Hydrochloric acid : * It is used in our homes for cleaning kitchen sinks and sanitary ware or clogged drains. * It is used for cleaning metal surfaces before tinning or galv
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Preparation And Properties Of Bases Bases * Substances with sticky nature and changing red litmus into blue an called as bases. * The substance which react with acids to form salt and w
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CLASSIFICATION BASED ON STRENGTH Strong alkali :- The alkalis which almost completely dissociates in an aqueous solution to produce high concentration of hydroxyl \( (OH^ - ) \
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PREPARATION OF BASE / ALKALI A) Action of oxygen on metals: Heat any metal like Magnesium, Calcium etc.. in presence of air to give its oxides. \( 4K + O_2 \xrightarrow{{}}
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BASES / ALKALI PROPERTIES A) Alkalis bitter in taste and have soap touch, i.e., a slippery sensation produces. B) Turns red litmus blue, phenolphthalein solutio
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Salts and Its Types SALTS A substance formed by the partial or complete neutralisation of hydronium ion of an acid with base is called salt. A salt essentially consists of metallic ion or ammonium
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Acid Salt The salt formed by the partial replacement of replaceable hydrogen ions of an acid by a basic radicals is called acid salts. The salt of strong acids and weak bases give acidic solutions.
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Water - Our Life Line WATER FOR LIFE Water is indeed essential to life on Earth, earning it the title of "our lifeline." It plays a crucial role in various biological, ecological, and en
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SEWAGE Sewage is a liquid waste and refers to a mixture of domestic, industrial, and sometimes stormwater runoff that contains water, human waste, soaps, detergents, and other debris. It is generated
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SANITATION, DISEASE AND SEWAGE DISPOSAL Sanitation, disease prevention, and sewage disposal are interconnected aspects of public health and environmental management. Proper sanitation practices and
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Physical Classification Of Matter Matter may be defined as anything that occupies space, possesses mass and presence of which can be felt by any one or more of our five senses (i.e. sight, smell, t
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CHARACTERISTICS OF PARTICLES OF MATTER * Particles of matter have spaces between them When potassium permanganate (KMnO4), dettol, sugar or salt are dissolved in water, then their particles
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Intermixing of particles of different types of matter on their own is called diffusion Experiment-3 : Take two beakers filled with water and put a drop of blue or red ink slowly along the sides of
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Illustrations Question 1: Kitchen salt (NaCl) when added to water, gets evenly distributed in it. Which characteristic of particles of matter is exhibited by this ? Solution: &
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Solid State Matter in solid state has a definite shape and definite volume. Examples: Silver, copper, sand, sugar, gold, ice, wood, stone, book, needle, pencil, piece of thread, etc. *Pro
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Liquid State The matter in liquid state have a definite volume and no definite shape. Examples : Water, blood, benzene, alcohol, milk, petrol, cooking oil, juice, cold drink etc. *Properties of
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Gaseous State The matter in gaseous state has neither definite volume nor shape. Examples : Air, oxygen, nitrogen, hydrogen, ammonia, carbon dioxide, compressed natural gas (CNG) etc. *Properti
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Experiment to illustrate comparison between solids, liquid and gases in terms of compressibility. &nb
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Plasma : Plasma (a mixture of free electrons and ions) is the fourth state of matter (e.g. fluorescent tube or neon sign) Plasma is an ionised gas, a gas to which sufficient energy is provide
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Examples Question:What is the general name of : (a) rigid form of matter ? (b) flui
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Interconversion Of Matter *Latent heat: The amount of heat required to change the state of matter from one state to another without rise in temperature is known as latent heat of that substance.&n
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EFFECT OF CHANGE OF TEMPERATURE Effect of temperature on the change of state of matter can be explained by the following experiment *Increasing the temperature by heating Experiment: Take
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*On decreasing temperature by cooling (i) Change of state from liquid to solid (solidification): When water is cooled (by lowering its temperature) it gets changed into solid ‘ice’. The
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*SUBLIMATION Sublimation is the process of conversion of a solid directly into a gas or vice-versa without changing into liquid state.
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EFFECT OF CHANGE OF PRESSURE The effect of pressure on the states of matter can be discussed by the following experiment. Experiment : Take a gas in a cylinder and apply pressure by pushing the pi
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SOLVED EXAMPLES Question:Convert the following temperature to Celsius scale : (a) 300 K (b) 573 K Solut
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EVAPORATION The phenomenon of change of a liquid into vapours at any temperature below its boiling point is called ‘evaporation’. Evaporation is a surface phenomenon i.e. only the parti
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Experiment: Step I : Take 5ml of water in a test tube and keep it under a fan. Step II : Take 5ml of water in an open china dish and keep it under a fan. Step III : Take 5 ml of water in an open ch
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SOME EXAMPLES OF COOLING CAUSED BY EVAPORATION FROM DAILY LIFE (i) Pouring of Acetone on palm : We feel cool when we pour some acetone on our palm. This is because, the energy ne
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SOLVED EXAMPLES Question: Why does a desert cooler cool better on a hot dry day ? Solution: A hot dry day means temperature of the atmosphere is high and humidi
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IS MATTER AROUND US PURE The chemical classification of matter : The chemical classification of matter is into two types 1) pure substances  
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ELEMENTS Definition: Substances, which cannot be broken further into any other substances by any physical or chemical means, are called ‘Elements’. Example : Hydrogen, oxygen,
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Metals If an element is a metal, it should have the following characteristics: (i) It should have lustre, i.e., it should have metallic glow. (ii) It should be a
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Metalloids : Some element have intermediate properties of the metals and non-metals. The elements which exhibit the properties of metals as well as non-metals, are called metalloids. Example : Boro
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COMPOUNDS A compound is a pure substance formed from two or more elements combined together in a definite proportion by weight. Properties of compounds: i)A compund cannot be separated into its c
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MIXTURES A mixture is a material containing 2 or more elements or compounds that are in close contact and mixed together in any proportion. The components of a mixture can be separated by simple mech
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SOLUTIONS A homogeneous mixture of two or more substances is called a solution. In a solution there is homogeneity at the particle level. Usually we think of a solution as a liquid that contains eith
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Concentration of a solution :– The concentration of a solution is the amount of solute present in a given quantity of the solution. In other words the mass of the solute in grams, which is prese
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*Saturated solution :– A solution which at a given temperature dissolves as much solute as it is capable of dissolving, is said to be a saturated solution. Ex.At 30°C, 55 g of common s
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*Suspensions :– A suspension is a heterogeneous mixture in which the small particles of a solid are spread throughout a liquid without dissolving in it. The particles have a tendenc
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*Colloidal solution or Colloids : A heterogeneous solution in which the particle size is in between 10–7cm to 10–5cm such that the solute particles neither dissolve nor sett
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Difference between true solutions and colloidal solutions Difference between colloidal solutions and suspensions
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Ions And Formula BEFORE LEARNING FORMULA OF A COMPOUND WE SHALL RECAP THE CONCEPT OF ELECTROPOSITIVE AND ELECTRONEGATIVE IONS Electropositive ions When an atom looses one or more electro
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Trivalent electropositive ions When an atom looses three electrons or if any Radical or ion has tripositive charge on it then it is known as Trivalent electropositive ion Tetravalent elect
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Electronegative Ions The species which carry negative charge on them (or) The species formed by gain of electrons by an atom are called Electronegative Ions. (or) Anions. Monovalent negative ions:
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Trivalent Electronegaive ions A Radical or Ion which is formed by gaining of three electrons is called Trivalent Electronegaive ions. Tetravalent negative ions A radical formed by gaining 4 ele
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FORMULA As already discussed, the elements are represented in the abbreviated form by their symbols. Similarly, a compound is represented in the abbreviated form by its chemical formula. Definitio
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Names and Formulae of a Simple Compounds The simplest compounds are binary compounds. A binary compound is a compound that contains atoms of only two different elements. For example, NaCl is a bina
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Writing formula of a Binary Molecular Compound In binary molecular compounds, the atoms of the two elements are held by covalent bonds. A covalent bond, as you know, is formed by sharing of electrons
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Writing formula of An Ionic Compound (or) Compound containing Radicals: The formula of an ionic compound represents the simplest whole number ratio of ions in it. The total positive charge on catio
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Worked Examples Example-1 Write the Formula of oxide of elements ‘X’ when its Valency is 3 Solution Symbols : X O
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Naming of Acids Naming acids involves specific rules based on the type of acid: binary acids or oxyacids. Below are the general rules for naming acids: Binary Acids: Binary acids consist of hydro
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Naming of bases Bases contaning -OH radical are names as hydroxides, after the name of metal. Examples: i) NaOH Sodium hydroxide. ii)
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Chemical Reactions COMBINATION, DECOMPOSITION,DISPLACEMENT, DOUBLE DISPLACEMENT REACTIONS Definition of chemical change: A change in which new substances are formed is called Chemical cha
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EXPERIMENT The chemical combination reaction can be well illustrated by conducting an experiment using calcium oxide and water which combine to form calcium hydroxide.  
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CHEMICAL DECOMPOSITION REACTIONS A decomposition reaction is a type of chemical reaction in which a single compound breaks down into two or more elements or new compounds. These reactions oft
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EXPERIMENT The chemical decomposition reaction can be well illustrated by conducting an experiment using Sodium Nitrate.Sodium Nitrate on heating decomposes to form sodium nitrite and oxygen. Th
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Chemical decomposition can occur in the following cases Case-i: A compound decomposes into two elements Example: When electric current is passed through acidified water, it decomposes to give hy
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CHEMICAL DISPALCEMENT REACTIONS A single-displacement reaction, is a chemical reaction in which one (or more) element(s) replaces an/other element(s) in a compound. It can be represented gene
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Metal displacement reaction: A chemical displacement reaction in which a metal is displaced from the compound is known as metal displacement reaction. For example , When a strip of magnesium meta
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EXPERIMENT Let us perform an activity using copper sulphate solution and iron nails to understand the chemical displacement reactions as follows The equation is as follows &n
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DOUBLE DISPLACEMENT REACTIONS A double displacement reaction is a type of reaction in which two reactants exchange ions to form two new compounds. Double displacement reactions typically result in
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EXPERIMENT Let us perform an activity using Silver nitrate, Sodium chloride to understand the chemical double displacement reactions as follows- Activity :Experiment: Apparatus:Two test tubes.
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Formation of a Precipitate in a double-displacement reaction A precipitate forms in a double-displacement reaction when the cations from one of the reactants combine with the anions from the other
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Formation of a Molecular Compound in a double-displacement reaction Another kind of double-replacement reaction is one that produces a molecular compound as one of its products. Many reactions can be
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Chemical Equations And Laws Chemical equations: A chemical change is represented by means of chemical equation by using various symbols and formulae. The substances which take part in the chemical
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How is an equation balanced? A chemical equation is balanced by assigning suitable co-efficients to the molecules wherever necessary by trial and error metho4) Balancing the equation.  
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Atomic mass: It is defined as number of times one atom of an element is heavier than \( \frac{1} {{12}}th \) wt of one atom of C-12. 1)t.W.t = \( \frac{{\text{Wt}\,\tex
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Laws of conservation of mass: This law was proposed by Lavoiser. This law states that mass can neither be created nor destroye This law is applicable to all chemical reactions. During a chemi
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Law of definite proportions: This law was given by Proust in 1799 and stated as: Irrespective of the method of preparation of a compound from two or more elements, they combine in a fixed ratio of
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Law of multiple proportions: This law was put forth by Dalton in 1808. According to this law, if two elements combine to form more than one compound, then the different masses of one element which
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Acids, Bases And Salts-Theories Introduction: Based on the nature, compounds are classified as acids, bases and salts. The term acid is derived from the latin word ‘acidium’ meaning so
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Postulates: A)A substance which contain one or more hydrogen atoms and which yield H+ ions in aqueous solution are acids. Examples: \( HCl_{(aq)} \text{ }\xrigh
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Limitations of Arrhenius theory: A)The definition of acids and bases are limited to aqueous solution only. B)Acidic nature of substances which do not contain H+ and basic nature of substances wh
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Example based on : Arrhenius Concept Ex.The characteristics of an acid is : A) turns blue litmus to red. B) turns phenolphthalein pink from colourless. C) de
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Lowry - Bronsted theory of acids and bases J.N. Bronsted and T.M. Lowry independently introduced a new concept to overcome the drawbacks of Arrhenius theory: Species which has capacity to donate p
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Amphoteric : Substances which can act as acid as will as base are known as amphoteric HCl + H2O H3O+ + Cl–
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Amphoteric : Substances which can act as acid as will as base are known as amphoteric HCl + H2O \(x = {-b \pm \sqrt{b^2-4ac} \over 2a}\) H3O+ + Cl– base
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A limitation of the Bronsted Lowery theory is that the extent to which a dissolved substance can act as an acid or a base depends largly on the solvent. A)HClO4 + HF \( \rightl
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Classification of Bronsted - Lowery Acids and Bases Bronsted - Lowery acids and bases can be (i) Molecular (ii) Cationic and &
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Classification of Solvents There are two types of solvents (i) Protonic (protic) and (ii) Aprotic (i)
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Levelling Solvents (i) The Bronsted - Lowery theory can be extended to acid - base reactions in non-aqueous solvents. It can be used in differentiating the acid strength of a particular acid
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Examples based on : Bronsted - Lowery Concept Ex.Select the aprotic solvent from the following is : A) H2O B) C6H6 C) HF D)
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Lewis or Electronic theory of acids and bases According to Lewis theory, an acid is any molecule, ion or atom which can accept a pair of electron to form a co-ordinate covalent bond. Example: H+, B
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Drawbacks of Lewis theory A)This theory does not explain about the strength of acids and bases. B)Acids like HCl, H2SO4 etc do not form dative bonds with bases. C)Acid base reactions are fast but
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Example based on : Lewis Theory Ex.In which of the following reaction does NH3 act as an acid ? A) NH3 + H+ \( \to \) NH4+ B) NH3 + Na \(
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Strength, Preparation and Properties Of Acids & Bases ACIDS: a substance with particular chemical properties including turning litmus red, neutralizing alkalis, and dissolving some metals; typ
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PREPARATION OF ACIDS 1.By direct combination of Elements. Acids are mostly prepared by a direct combination of elements. For example, hydrogen chloride gas is prepared from hydrogen and chlorine u
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PHYSICAL PROPERTIES OF ACIDS i)All the acids are colourless, though sulphuric acid may be brown at times due to impurities. ii)Acid taste sour. iii)Acid turn blue litmus red and methyl orange pin
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CHEMICAL PROPERTIES OF ACIDS 1.Action with metals: Metals displace hydrogen from the acids. They release hydrogen gas. \( Zn + HCl\xrightarrow{{}}ZnCl_2
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BASES / ALKALI Bases: *Substances with sticky nature and changing red litmus into blue an called as bases. *The substance which react with acids to form salt and water as the only products are ca
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PREPARATION OF BASES A)Action of oxygen on metals: Heat any metal like Magnesium, Calcium etc.. in presence of air to give its oxides. \( 4K + O_2 \xrightarrow{{}}
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BASES/ALKALI PROPERTIES A)Alkalis bitter in taste and have soap touch, i.e., a slippery sensation produces. B)Turns red litmus blue, phenolphthalein solution pink, methyl orange yellow and turmeri
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Electric Current INTRODUCTION *Electricity travels along a path. *The whole path along which electricity travels is known as a circuit. *The flow of current from +ve terminal to -ve terminal is
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Conductors: The materials that allow electric current to pass through them. Examples: Iron nail, copper wire, brass key, aluminium rod, pencil lead (graphite), mercury..etc. *All metals are go
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Light INTRODUCTION 1.Light is the form of energy which which makes objects visible to our eye. 2.The branch of physics which deals with the nature of light, its sources, properties effect and vis
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General definitions of light: 1.Optical medium: Any thing (material or non-materials), through which light energy passes wholly or partially, is called optical medium. Ex: vacuum, air, most
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Shadows: Shadow: Dark patch formed behind an opaque body, when the opaque body is placed in the path of light is called shadow.  
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Fun With Magnets INTRODUCTION: Magnetic phenomena are universal in nature. Vast, distant galaxies, the tiny invisible atoms, men and beasts all are permeated throug h and through with a host
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POLES OF MAGNET Example1: The magnetic effects are not same throughout the magnet .What would happen if we dip a magnet into a box of paper clips? most of the clips would stick to the ends of a ma
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Heat LEARNING OBJECTIVES * Heat and temperature. * Thermometric scales. * Heat capacity, water equivalent and specific heat. * Change of state. * Latent heat. * Principle of Calorimetry
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How is Heat Transferred? Heat can travel from one place to another in several ways. The different modes of heat transfer includes 1.Conductio 2. Convection3. Radiation. Meanwhile, if the te
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Friction In this lesson you will learn about * Friction, Advantages and disadvantages * Methods of minimising friction * Normal reaction *Types of friction *Motion on a Horizon
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Applications and Implications: Traction in Vehicles: Adequate friction between tires and the road is crucial for vehicle traction. Tread patterns on tires help increase friction and prevent skiddi
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Electric Circuits And Currents INTRODUCTION The flow of water in a river constitutes a current of water. Flow of heat in a conductor is called thermal current. Similarly flow of charges i.
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Heating effect of electric current Heating effect of electric current:The heating effect of electric current, also known as "Joule heating" or "resistive heating," is a phenomen
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Magnetic effect of electric current Magnetic effect of electric current: The magnetic effect of electric current is a phenomenon where an electric current flowing through a conductor produces a ma
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Sound Sound:- Sound is a form of energy which emitted by a vibrating body that travels in the form of waves and causes the sensation of hearing sound cannot travel through vacuum. The
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Characteristics of sound:- Pitch:- 1. The pitch of a sound is the characteristic which distinguishes between a shrill (or sharp) sound and a grave (or flat) sound. 2. A sound of high
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Variation of velocity of sound in a gas with temperature. The velocity of sound in a gas v = \( \sqrt {\frac{{\gamma p}} {\rho }} \) \( v = \sqrt {\frac
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Light INTRODUCTION: Nature has endowed the human eye (retina) with the sensitivity to detect electromagnetic waves within a small range of the electromagnetic spectrum. Electromagnetic radiation
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REFLECTION FROM PLANE SURFACES I)When you look into a plane mirror, you see an image of yourself that has three properties i)The image is up right (ii) The image is the same size as you are
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INSIDE OF EYE: The eye is probably the most important optical instruments. In principle, an eye can be compared to a photographic camera. In a camera, the aperture of the lens has to be adjusted. B
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Some Natural Phenomena In this chapter we shall discuss two destructive natural phenomena. These are lightning and earthquakes. We shall also discuss what steps we can take to minimise destruction
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CHARGING BY RUBBING: Charging by rubbing, also known as triboelectric charging or tribocharging, is a phenomenon where certain materials become electrically charged after they come into contact wit
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Types of Charges: Positive Charge (+): Protons carry a positive charge. In most normal matter, protons are bound within atomic nuclei. Negative Charge (-): Electrons carry a negative charge. Ele
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Transfer of Charge: The transfer of charge refers to the movement of electric charge from one object to another. There are several ways in which charge can be transferred, and these processes are f
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Stars And Solar System Observing the night sky is a fascinating experience for everyone. You might have watched the clear blue sky some times and also have observed sunrise and sunset several times
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Stars and Solar System: The planets: The planets look like stars, but they do not have light of their own. They merely reflect the sunlight that falls on them. A planet has a definite path in whi
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Kinematics Or Motion In A Straight Line Distance, Displacement, Speed and Velocity Introduction Kinematics is the science of describing the motion of objects using words, diagrams,numbers,
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Speed And Velocity Speed: The distance travelled by the body in unit time is called its speed. Speed (V) = \( \frac{{Dis\tan cetravelled}} {{Timetaken}
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Displacement-time graphs:These graphs are down by ploting displacement on Y-axis and time on X-axis .Slope of this graph gives velocity a)If the graph is a straight line parallel to time axis,then
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Newton's Laws Of Motion NEWTONS FIRST LAW:If no external force acts, a body continues to be in its state of rest or of uniform motion along a straight line. &n
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NEWTON’S SECOND LAW OF MOTION 1.The rate of change of momentum of a body is directly proportional to the external force and the change in momentum takes place in the direction of the force. 2.
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Newton's 3rd Law Of Motion NEWTON’S THIRD LAW We have seen above that Newton's first law of motion defines force. The second law establishes a relation between the external for
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LIGHT REFRACTION OF LIGH When a beam of light is travelling from one medium to another medium, a part of light gets reflected back into firstmedium at the inferface of two media and the remainin
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REFRACTIVE INDEX: I)Absolute refractive Index (µ): The absolute refractive index of a medium is the ratio of speed of light in free space (C) to speed of light in a given medium (V).
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OPTICAL PATH (\(\Delta\)x): The shortest distance between any two points A and B is called geometrical path. The length of geometric path is independent of the medium that surrounds the path AB. Wh
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REAL AND APPARENT DEPTHS(NORMAL SHIFT) As a consequence of refraction, the depth of an object lying inside an optically denser medium appears to be less than its real depth. Obect is in de
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Work-Power-Energy LEARNING OBJECTIVES: ¨ Work and it’s nature. ¨ Expressions for workdone in different cases. ¨ En
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ENERGY ¶¶ Introduction to Energy It is often said that a person A is more energetic than a person B. The meaning of this s
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Gravitation Newton's law of universal gravitation Derivation of Newton's law of universal gravitation Newton's law of gravitation, states that every par
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THRUST AND PRESSURE: A liquid exerts pressure.To show it,consider a vessel containing a liquid.If it has a small hole near the bottom,the liquid will flow out of it.If the motion of the liquid is s
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ARCHEMEDE’S PRINCIPLE: It states that when a body is immersed completely or partly in a liquid, it loses it’s weight which is equal to weight of liquid displaced Let W1 be weight
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Sound Sound:- Sound is a form of energy which emitted by a vibrating body that travels in the form of waves and causes the sensation of hearing sound cannot travel through vacuum.The concept of so
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Characteristics of sound:- Pitch:- 1. The pitch of a sound is the characteristic which distinguishes between a shrill (or sharp) sound and a grave (or flat) sound. 2. A sound of high pitch is sai
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Variation of velocity of sound in a gas with temperature. The velocity of sound in a gas v = ()
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Heat SPECIFIC HEAT JOULES LAW & MECHANICAL EQUIVALENT OF HEAT Statement of Joule's Law: Whenever work is done against friction, heat is generated. The amount of heat generated (
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VECTORS Physical quantities: All measurable quantities are called physical quantities. Physical quantities are classified into scalars and vectors. Scalar Quantities: Physical quan
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Types of vectors 1) Equal vectors: If two vectors have same magnitude and direction they are said to be equal vectors. &n
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Angle between two vectors To find angle between two vectors, the two vectors from a point are drawn such that they should either co initial or co terminal. The shortest angle obtained in this way,
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Vectors-Displacement, Addition, Subtraction And Multiplication Of Vectors Physical quantities : The quantities that are measurable are called physical quantities Ex: Length, Mas
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LAWS OF VECTOR ADDITION Vector addition follows commutative,associative and distributive laws. a) Commutative law : \( \overline {A} + \overline B
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Subtraction of a vector from another vector The subtraction of one vector from the other is a special case of addition of two vectors in which one vector is compounded with the negative
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Multiplication of a vector with a scalar : a) When a vector is multiplied by a scalar, the resultant is also a vector. b) \( \overrightarrow A = s\overrightarrow B \), If s is posi
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Newton's first Law Of Motion INTRODUCTION In unit II,we studied the kinematics of motion by developing the concepts of displacement velocity and acceleration and by deriving relations between
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NEWTON’S FIRST LAW OF MOTION OR LAW OF INERTIA Newton’s first law of motion states that every body continues in its state of rest or of uniform motion in a straight line,unless it is co
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APPLICATIONS OF INERTIA Following examples from our daily life illustrate the law of inertia: 1.When a running horse suddenly stops,the rider falls forwards.Because the lower part of the b
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Momentum LEARNING OBJECTIVES ¨ Linear momentum. ¨ Change in linear momentum. Important Formulae: 1. P= mv &
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Change in momentum of a body in different cases Consider a body of mass m moving with velocity \( \vec V_i \) and momentum \( \vec P_i \) . Due to a collision (or) due to the action
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Newton's Second Law Of Motion Learning objectives: ¨ Newton’s second law of motion. ¨ Impulse. ¨ Newton’s third law of moti
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Newton's Third Law Of Motion Newton's Third Law Of Motion To every action there is always an equal and opposite reaction Action and reaction do not occur on the same body they act o
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Law of conservation of linear momentum Collision: If a number of bodies collide with one another then total momentum of the bodies, just before collision is equal to the total momentum just a
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Forces In Nature There are following four kinds of forces(or interaction)operative in nature: 1.The gravitational force 2.The weak force 3.The electromagnet
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1.The Gravitational force.[G.F]It is the force of attraction between two objects due to their masses and is governed by Newton’s law of gravitation.The force of attraction between two objects of
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3.The Electromagnetic force. [E.M.F]The electric and magnetic forces are the two facets of electromagnetic force.The force between two static (at rest)electric charges is governed by Coulomb’s l
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Muscular force:It is a type of contact force where force is applied by touching it Due to these forces muscles in our body expand due to conatct. ex:-In the following examples our muscles do work. (
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Work In ordinary language the word ‘’Work’’ means any physical or mental activity but in physics, Work is said to be done by a force if the point of application of force un
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NATURE OF WORK ¶¶ POSITIVE WORK:
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Energy "Energy of a body is it’s capacity to do work" Greater the amount of energy possessed by the body, greater the work it will be able to do. All the agents which are able to d
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KINETIC ENERGY The energy possessed by a body by virtue of its motion is called kinetic energy. Examples for body having kinetic energy ; (i) Flowing water possesses kinetic energy which
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Expression for kinetic energy Let m = mass of the body, &
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POTENTIAL ENERGY Potential energy of a body is the energy possessed by a body by virtue of its position or configuration * It is measured by the work that the body can do in position or confi
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MECHANICAL ENERGY 1.The sum of potential and kinetic energy of a system is known as mechanical energy E=U+K where U is P.E and K is K.E Here K is always positive and U may be positive or n
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Power Power 1. Power is the rate of doing work. It is scalar. 2. Power = \( \frac{{workdone}} {{time}}\, = \,\frac{W} {t} \) 3. Units of power : erg s-1 (CGS)
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EFFICIENCY OF CRANE OR MOTOR The ratio of output power to the input power is called efficiency. \( \eta = \frac{{output\,power}} {{Input\,power
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Pressure A liquid exerts pressure.To show it,consider a vessel containing a liquid.If it has a small hole near the bottom,the liquid will flow out of it.If the motion of the liquid is stopped by pr
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ATMOSPHERE AND ATMOSPHERIC PRESSURE The earth is surrounded by a gaseous envelope extending upto a few thousand kilometres.This gaseous envelope is made of 78% nitrogen,21% oxygen and a small
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ARCHIMEDES PRINCIPLE It states that when a body is immersed completely or partly in a liquid ,it loses in weight equal to the weight of the liquid displaced by it Let w1 be the weight of a body in
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Newton’s Third Law Of Motion Defnition: To every action there is always an equal and opposite reaction Action and reaction do not occur on the same body they act on different bodies at
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IMPULSE: 1. when a large force acts on a body for a short interval of time the change in linear momentum of the body is called impulse. 2. Impulse \( \overrightarrow I = \overrightarrow F t
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Law of conservation of linear momentum: Collision: If a number of bodies collide with one another then total momentum of the bodies, just before collision is equal to the total momentum just
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Work Real life applications : . The main advantage of using Work and Energy methods is that it allows you to easily find the velocity of a body or system of bodies knowing how much "work
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NATURE OF WORK ¶¶ POSITIVE WORK: &
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EXPRESSIONS FOR WORKDONE IN DIFFERENT CASES 1) The work done in lifting a body of mass m having density d1 inside a liquid of density d2 through a height h is (a=0) \( W = mgh\left( {1
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Energy ENERGY-SOURCES-FORMS OF ENERGY ¶¶ Introduction to Energy It is often said that a person A is more energetic
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KINDS OF ENERGY In actual practice there are many kinds of energy, such as mechanical energy; heat energy; light energy; sound energy, electrical energy; nuclear energy; chemical energy, etc. Let u
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¶¶ Mechanical energy (M.E) The sum of kinetic energy (K.E) and potential energy (P.E) of a body is known as mechanical energy
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¶ ¶ Potential Energy:- The energy possessed by a body by virtue of its state or position is known as potential energy. Expression for gravitational potential e
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¶¶ Gravitational potential energy :- The Potential energy due to height above the earth’s surface is called gravitational potential energy. In general, if the potential en
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¶¶ Sound Energy:- Sound is a form of energy, that is produced by a body when it is in the state of vibration. It propagates in the form of Longitudinal waves through
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§§ Other forms of energy :- Besides mechanical energy, energy can exist in several other forms. Charged particles and electric currents can produce electrical energy and magnetic ener
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Relation between kinetic energy and momentum Let us consider a body of mass ‘m’ having a velocity ‘v’ , then momentum of the body P = mass &t
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Power Power 1. Power is the rate of doing work. It is scalar. 2. Power = \( \frac{{workdone}} {{time}}\, = \,\frac{W} {t} \) 3. Units of power : erg s-1 (CGS),Js-1 or Watt (S
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APPLICATIONS OF POWER 1) if a machine gun fires 'n' bullets per second such that mass of each bullet is 'm' and comming out with a velocity 'v' then the power of the machine
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5) A body of mass 'm' is initially at rest. By the application of constant force its velocity changes to "V0" in time ' to' then \( \begin{gathered
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Introduction, Types And Friction Of Horizontal Surface FRICTION Introduction: The classic rules of sliding friction were discovered by Leonardo da Vinci (1452–1519) but remained unpublish
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METHODS OF REDUCING FRICTION * POLISHING : Friction can be reduced by making the surface in contact polished and smooth. This will remove
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TYPES OF FRICTION There are three types of friction. Static friction Dynamic or Kinetic friction Rolling friction Static friction: The opposing force that comes Types of friction into
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Limiting friction: ‘The maximum value of static friction that develops on a body when the body just tends to slide over the surface of another body is called the ‘limiting friction&rsqu
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Dynamic Friction or Kinetic Friction: If the applied force is increased further and sets the body in motion, the friction opposing the motion is called kinetic friction. When the applied force inc
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Rolling friction: When objects such as a wheel (disc or ring), sphere or a cylinder rolls over a surface, the force of friction that comes into play is called rolling friction. Rolling friction
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Distinction between static and kinetic friction When the body is at rest over the surface of another body the frictional force increases from zero to maximum value with the pulling force. The variati
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Angle of friction: Angle between normal reaction and resultant of frictional force(F) and normal reaction(R) is called angle of friction(\(\theta\)) &nb
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Law Of Gravitation GRAVITATION We have discussed various forces : pushes and pulls, elastic force, friction and other forces that act when one body is in contact with another. In this chapter we s
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GRAVITATIONAL CONSTANT “G” (i) Gravitational constant is a scalar quantity. (ii) UNIT : S I : G = 6.67 × 10–11 N-m2/kg CGS 6.67 × 10–8 dyne-cm2/g2&nbs
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RELATION BETWEEN G AND g We want to measure g due to M at a point P as per the procedure. place a point mass m at P measure the force imparted by M on the test mass m. this is equal to Fg=
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Thrust And Pressure TYPES OF PRESSURE Atmospheric pressure (Patm): Atmospheric pressure is the pressure exerted by environmental air. (or) The force exerted by atmosphere per unit area on th
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PRESSURE IN A FLUID When a fluid (either liquid or gas) is at rest, it exerts a force perpendicular to any surface in contact with it, such as a container wall or a body immersed in the fluid. Whi
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Variation of Pressure in a static fluid Let us consider a container filled with water. Density of water can be taken as uniform through out the container. Let A and B be two points inside the water l
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BAROMETER The instrument used for measuring of pressure is called Barometer. It was constructed by Torricelli in 1643. It consists of a glass tube with a narrow uniform bore and of length 10
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MANOMETER It is a device used to measure the pressure of a gas inside a container. The U-shaped tube often contains mercury. P1 = P2 &nb
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Buoyant Force BUOYANT FORCE When an object is immersed in a liquid, it experiences an upward force. This force is called buoyant force. Let us consider a cylindrical object of height &lsquo
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ARCHIMEDE’S PRINCIPLE Force of buoyancy acting on a body immersed partly or wholly in a static fluid is numerically equal to weight of the fluid displaced and is directed vertically upwards.
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RELATIVE DENSITY OF ARCHIMEDE’S PRINCIPLE According to Archimedes principle, apparent loss of weight of a substance immersed in a liquid is equal to weight of displaced liquid . This principl
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Buoyant Force in Accelerating Fluids Suppose a body is dipped inside a liquid of density \( \rho _L \) placed in an elevator moving with an acceleration \( \mathop a\limits^ \to \). The
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Laws Of Flotation FLOTATION When a body of density \(\rho_b\) and volume V is immersed in a liquid of density \(\rho_L\), the force is acting on the body are: (1) Weight of the body W = mg
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Laws of floatation : 1. The weight of floating body is equal to the weight of liquid displaced. 2. The centre of gravity of the floating body and the centre of buoyancy (centre of gravit
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APPLICATIONS 1. Animals have soft skeletons (unlike those of terrestrial) : The density of animals and fish living in water is almost same as the density of water. Therefore their weight is al
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Change Of State (i) Change of state from solid to liquid (fusion): When heat is supplied to a solid (ice), the kinetic energy of solid particles increases due to increase in temperature. As a resul
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Decreasing Temperature By Cooling (i) Change of state from liquid to solid (solidification): When water is cooled (by lowering its temperature) it gets changed into solid ‘ice’. The pro
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SUBLIMATION Sublimation is the process of conversion of a solid directly into a gas or vice-versa without changing into liquid state.  
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LATENT HEAT 1.The amount of heat gained or lost by unit mass of a subastance at a constant temperature is called specific latent heat or heat of formation(L) 2.Specific latent heat or
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Different states of matter
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Triangle Law And Polygon Law Triangular law of vector addition Statement - 1: If two vectors are represented both in magnitude and directio
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Sine rule: In any triangle the length of the side is proportional to the sine of the angle opposite to it. (or) \( \frac{a} {{\sin A}} = \frac{b} {{\sin B}} = \frac{c} {{\sin C}} \)  
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Equilibriant Vector A single vector which balances two or more vectors acting on a body at the same time is called an equilibrant vector. It is equal and opposite to the resultant of various ve
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Tangent Formula (Application of lami's theorem) Let a bob of mass m suspended to the ceiling by means of a light string of length l is pulled by a horizontal force F till the weight of the bob,
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polygon law of vector addition: If several vectors are represented both in magnitude and direction as the adjacent sides of a polygon taken in order then the closing side taken in reverse order rep
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Dot Product DOT PRODUCT OF VECTORS Multiplication of Vectors A vector multiplied by another vector may give a scalar or a vector. Hence there are two types of products for mul
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Properties of Scalar Product: 1) Scalar product of two parallel vectors is maximum \( \overrightarrow A .\overrightarrow B = \left| {\overrightarrow A } \right|\left| {\overrightarrow B }
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Applications of Dot Product i) Angle between two vectors and can be found from \( \cos \theta = \frac{{\overrightarrow {A.} \overrightarrow B }} {{\ov
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Examples of dot product : 1) Work done is the dot product of force and displacement W =\( \vec F.\,\vec S = FS\cos \theta \) . 2) Power is the dot product of force and
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Cross Product Vector Product or Cross Product If \(\vec A\) and \(\vec B\) are two vectors and the angle between them is \(\theta\) then the cross product of these two vectors
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Laws of Vector product: a) Cross product does not obey commutative law. \( \overrightarrow A \times \,\overrightarrow B \ne \,\overrightarrow B \times \overrightarrow
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Properties of cross Product: 1) If \( \hat{i},\hat{j},\hat{k} \) are unit vectors then \( \hat{i} \times \hat{i} = \hat{j} \times \hat{j} = \hat
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Examples of cross product : i) Angular momentum \( \mathop L\limits^ \to = \mathop r\limits^ \to \times \mathop P\limits^ \to \) ii) Linear velocity \( \mathop V
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Applications of cross product : (i) The area of triangle formed by \( \overrightarrow A \& \,\overrightarrow B \) as adjacent sides is \( \frac{1} {2}\left| {\overrightarro
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Speed And Velocity §§ Introduction Kinematics is the science of describing the motion of objects using words, diagrams, numbers, graphs, and equations. Kinematics is a branch
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§§ Rest: A body is said to be at rest if it does not change its position with respect to the reference point. The objects which remain stationary at a place and do not change their position
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§§ Speed: The distance travelled by the body in unit time is called its speed. Speed (V) = \( \frac{{Dis\tan cetravelled}} {{Timetaken}} \) *s
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§§ Velocity: The rate of displacement (or) displacement per unit time is called velocity.
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Acceleration ACCELERATION If the velocity of a particle is changing as it moves then it is said to be moving with acceleration The acceleration measures how rapidly the velocity is changin
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INSTANTANEOUS ACCELERATION The acceleration of a particle at a particular instant of time is called it's instantaneous acceleration. It is also defined as the limit of average acceleration as th
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Equations Of Motion The relation between v, u,a and s for a body moving with uniform acceleration in a straight path are well known to us. Equations which relate these quantities are known as e
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DERIVATIONS OF EQUATION OF MOTION 1) Derivation for the Equation of Motion v = u+at Consider a body having initial velocity ‘u’. Suppose it is subjected to a uniform acceleration
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2) Derivation for the Equation of Motion s = ut+at2 Velocity is defined as the rate of change of displacement. This is mathematically represented as: \( Velocity = \
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3) Derivation of Third Equation of Motion v2- u2 = 2as For the derivation of the third equation of motion, consider the same variables that were used for the derivation of th
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(d) Displacement in nth second of motion. Consider that an object starts moving with initial velocity u and the uniform acceleration a. Let the displacement of the object in the nth second of its moti
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WORKED EXAMPLES Ö Example-1:If a sports car at rest accelerates uniformly to a speed of 144 km h-1 in 5 s then find distance travelled by it ? Sol : \( \begin{gathered} u = 0,v
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Freely Falling Body MOTION IN A LINE - FREELY FALLING BODY Consider the case of an object moving in uniformly accelerated motion along a straight line OX with origin at O as shown in figure .Let i
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ACCELERATION DUE TO GRAVITY(G) The uniform acceleration of a freely falling y towards the centre of earth due to earth's gravitational force is called acceleration due to gravity. i)It is deno
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Body Falling Freely under Gravity the initial velocity is zero (i.e., u = 0 and a=g) The equations of motion of a body falling freely are) (i)v=u+at v=gt------(e) (ii)\( S = ut + \frac{1} {2}at
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TIME OF DESCENT Time taken by the freely falling body to reach the ground from the point of dropping is called time of descent.It is denoted by td.. From 
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VELOCITY WITH WHICH THE BODY REACHES from \( v^2 - u^2 = 2as \) In case of freely falling body u=0,a=g S= distance travelled by t
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Important Conclusions from above Equations: 1) From eq(f) , i.e., the distance fallen in time t,2t,3t,.........etc.will be in the ratio \( 1^2 ,2^2 ,3^2 ,.....etc \). &nb
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Vertically Projected Body ACCELERATION DUE TO GRAVITY(G) The uniform acceleration of a freely falling y towards the centre of earth due to earth's gravitational force is called acceleration du
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Equations of motion for a body projected vertically upwards In case of a body projected vertically upwards a = -g final velocity (v) = 0 at its highest point(maximum height). Th
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(i)Time of ascent (ta) : "For a body projected upwards the time to reach the maximum height is called time of ascent" Expression : Let a body be projected vertically upwards with
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(ii)Time of descent (td): "For a body projected upwards the time to travel from maximum height to the point of projection on ground is called time of descent" Expression : Let a body be p
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(iii)Time of flight (T) : It is defined as the time for which a body remains in the air. T=td+ ta
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(iv)Maximum Height (H) : Maximum height (Hmax): "For a body projected vertically upwards, the maximum vertical displacement from ground about which its velocity is zero is called its maximum hei
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(v)Velocity of the body on reaching the point projection (\( V_{striking} \)) Let a body be projected vertically upwards with initial velocity u. The body reaches the point of projection once a
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Some points related to vertically projected body: 1.A body projected vertically up travels a distance ‘S’ in the nth second.Distancetravelled by it in the (n+1)th second is (S-g)
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WORKED EXAMPLES Ex 1:A stone is dropped from top of a tower 300m high and at the same time another is projected vertically upward with a velocity of 100 . Find when and where the two stones m
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Graphs[S-T, V-T, A-T] Displacement-time graphs: These graphs are down by ploting displacement on Y-axis and time on X-axis .Slope of this graph gives velocity a)If the graph is a straight line pa
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VELOCITY-TIME GRAPHS This graph is plotted by taking velocity on Y-axis and displacement on X-axis slope of this graph represents acceleration.Area under this graph gives displacement a)If the gra
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f)For a body projected vertically up from the top of a tower,graph will be as shown.Area below the graph gives -h where h is tower height.  
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ACCELERATION-TIME GRAPHS This graph is drown by plotting acceleration on Y-axis and time on X-axis .Area below the graph gives change in velocity. a)For a body moving with uniform acceleration,gra
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Relative Motion RELATIVE VELOCITY 1.If \(\vec v_A\) and \(\vec V_B\) are the velocities of A and B then relative velocity of A with respect to B is \(\vec V_A -\vec V_B\) and
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MOTION OF BOAT IN A RIVER 1. Let \(\vec U\) be the velocity of boat in still water.is \(\vec V\) velocity of water in a river.If the boat moves in that river,its resultant velocity i
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8. If the boat crosses in the shortest time, resultant velocity of the boat is \( |\overrightarrow U + \overrightarrow V | = \sqrt {u^2 + V^2 } \) in magnitude resultant displacement i
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RAIN-UMBRELLA PROBLEM 1.Rain is falling vertically downwards with velocity \(\vec U\).A person is walking on a road with velocity \(\vec V\).In order to protect himself from rain he must hold
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Motion In A Plane §§ PROJECTILE Projectile is any body projected into the air at an angle othe than 90o with the horizontal near the surface of the earth. The path followed by
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a) Time of ascent :- Time Taken to Reach Maximum Height. We let this time be denoted ta. At the maximum height the vertical velocity is zero i.e.,Vy=0 &
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d) Horizontal Range : - The horizontal distance travelled by the projectile while it touches the point on the same level of the point of projection is called horizontal range. In
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§§ Vector notations incase of projectile motion a) Velocity after some time : Initital velocity the projectile \( \overrightarrow v = \left(
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b) Velocity after some hegiht \( \begin{gathered} \overrightarrow v = u\cos \theta \,\hat{i} + \left( {u\sin \theta } \right)\hat{j} \hfill \\ \overright
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c) Position vector of the particle \( \vec U = \left( {u\cos \theta } \right)\hat{i} + \left( {u\sin \theta } \right)\hat{j} \) &n
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(d) Position, Time and speed at any angular elevation Let a particle be projected with v0 at an angle \(\theta_0\) .After a time t it moves with a velocity v at an angle \(\thet
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§§ Radius of curvature at any point on the path of a projectile Let at any time t the velocity vector \(\vec v\) be inclined at
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CIRCULAR MOTION When a particle moves in a circular path with uniform speed, the direction of its velocity changes at every point on the circumference of the circle continuously. But the magnitude
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Definition : Centripetal Force: Centripetal force is the net or unbalanced force required by a body to perform uniform circular motion. &nb
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7.When an electron moves round the nucleus in a circular orbit,the electrostatic force between the electron and nucleus is the centripetal force. 8.If an electron of mass ‘m’ and charge &
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Centripetal acceleration: When a particle moves in a circle,an acceleration acts towards the centre which changes the direction of its linear velocity.This acceleration is called normal acc
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CENTRIFUGAL FORCE 1.The pseudo force which acts radially outwards on the body moving along a circle is called centrifugal force. 2.Even through centripetal and centrifugal forces are equal in magn
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CONICAL PENDULUM If the bob of a simple pendulum is pulled to a side and whirled to move along a circle in horizontal plane, the string sweeps a cone and this arrangement is called conical pendulum
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Circular Motion 2 RIGID BODY A body which does not undergo any change in shape or size by the application of external force is called a rigid body.Further, a rigid body is that body in which the d
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ROTATIONAL MOTION In general ,there are two types of motion: (i) translatory (ii) rotatory We may, in any particular cas
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ROTATIONAL KINEMATICS RELATIONS let the axis of ratation be passing through O and is perpendicular to the plane of the paper ,i.e., Z-axis is the axis of rotation. &nbs
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AXIS OF ROTATION: The axis of rotation refers to an imaginary line around which an object rotates or spins. In simple terms, it's the central line about which an object's movement occurs. T
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ANGULAR VELOCITY Angular velocity:The rate of change of angular displacement is called angular velocity.it is denoted by \( \omega \) ,units are rad/sec. Let the body be rotating in counter c
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ANGULAR ACCELERATION The angular acceleration of a rigid body is the rate of change of angular velocity of the body about the given axis of rotation. If angular speed \(\omega\) o
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EQUATIONS OF CIRCULAR MOTION AND COMPARISON WITH EQUATIONS OF TRANSLATIONAL MOTION
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Laws Of Motion FUNDAMENATLS OF STRINGS: 1. A string is assumed to be inextensible,i.e., perfectly elastic and massless. 2. The magnitude of accelerations of a number of bodies connected through &
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MOTION OF BODIES IN CONTACT : If two bodies with masses m1 and m2 are lying in contact on a horizontal smooth table and a force F is applied on the mass m1, then equal acceleration is produced
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b) When the force F acts on the body with mass m2: The acceleration produced i
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c) When three bodies of masses m1,m2 and m3 are lying in contact on a horizontal smooth table and a horizontal force F on a body of mass: Ac
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§§ MOTION OF BODIES CONNECTED BY STRINGS i) When two bodies of masses m1 and m2 are tied to the ends of a light string placed on the smooth horizontal surface, these are pulled
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MOTION OF BODIES CONNECTED BY STRING PASSING OVER A SMOOTH PULLEY Case-I: AT WOODS MACHINE: Let two bodies of masses m1 and m2 respectively are connected by a light inextensible string passi
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GRAVITATION Newton's law of universal gravitation Derivation of Newton's law of universal gravitation Newton's law of gravitation,
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Relation Between Universal Law Of Gravitation (G) and Acceleration due to gravity (g): Let us consider the earth to be made of large number of concentric s
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a)In terms of Radius (R) and Mean Density \(\rho\) we know that \( g = \frac{{Gm}} {{R^2 }} \) \( \begin{gathered} M = \left[ {\frac{4}
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b)In terms of Mass (M) and Density \(\rho\) As \( g = \frac{{Gm}} {{R^2 }} \) \( \begin{gathered} M = \left[ {\frac{4} {3}\Pi R^3 } \right]\rho \Rightarrow R
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VARIATION OF ‘G’ ABOVE THE SURFACE OF THE EARTH (OR) WITH ALTITUDE: Altitude refers to the height measured from the surface of the earth. Consider a body of mass m at a height h from t
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VARIATION OF g WITH DEPTH Let us assume that the earth to be a homogeneous uniform sphere of radius ‘R’,density \(\rho\) and mass ‘M’Now &n
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Differentiation FUNCTION Constant : A quantity, whose value remains unchanged during mathematical operations, is called a constant quantity. The integers, fractions,\( \pi \) , e, etc are
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DIFFERENTIATION: The derivative or differential coefficient of a function is the limit to which the ratio of the small increment in the function to the corresponding small increment in the variable
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Physical meaning of \( \frac{{dy}} {{dx}} \): The concept of differentiation is made use of in physics in determining the instantaneous rate of change of a physical quantity w.r.t. some othe
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4.03. THEOREMS OF DIFFERENTIATION 1. If c is a constant, then \( \frac{d} {{dx}}\left( c \right) = 0 \) 2. If y = cu, where c is a constant and u is a function of x, then \( \frac{{d
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FORMULAE FOR DIFFERENTIAL COEFFICIENTS OF TRIGONOMETRIC, LOGARITHMIC AND EXPONENTIAL FUNCTIONS 1. \( \frac{d} {{dx}}\left( {\sin x} \right) = \cos x \)  
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MOTION UNDER GRAVITY ACCELERATION DUE TO GRAVITY(G) The uniform acceleration of a freely falling y towards the centre of earth due to earth's gravitational force is called acceleration due to
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EQUATIONS OF MOTION FOR FREELY FALLING BODY Motion of all the dropped bodies falling rds the Earth when air resistance is ignored is mown as free fall. For a freely falling body, u=0, a=+g (i)v=u
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Time of descent: Time taken by the freely falling body to reach the ground from the point of dropping is called time of descent.It is denoted by td.. From&nbs
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VERTICALLY PROJECTED BODY EQUATIONS OF MOTION FOR VERTICALLY PROJECTED BODY For a body projected vertically upwards, a = g (since velocity, acceleration vectors are opposite) (i) v=u+at v=u-gt (
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MOTION PARAMETERS OF A BODY PROJECTED VERTICALLY UPWARDS (i) Maximum height (Hmax): "For a body projected vertically upwards, the maximum vertical displacement from ground about which i
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(ii)Time of ascent (ta): "For a body projected upwards the time to reach the maximum height is called time of ascent" Expression : Let a body be projected vertically upwards with initial
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iii)Time of descent (td): "For a body projected upwards the time to travel from maximum height to the point of projection on ground is called time of descent" Expression : Let a body be p
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iv) Time of flight (tf): "For a body projected vertically upwards the sum of time of ascent and time of descent is called time of flight (tf)" It is the total time for which the body r
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v)Velocity of the body on reaching the point projection (\( V_{striking} \)) Let a body be projected vertically upwards with initial velocity u. The body reaches the point of projection once agai
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Special cases: 1. Velocity at half maximum height =\( \frac{u} {{\sqrt 2 }} \) sol: Using the equation \( v^2 - u^2 = 2as \),we have a=-g \
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4.Distance covered by a body projected vertically up in the last one second of its upward journey = Distance covered by it in the 1st second of its downward journey = Sol. For a body falling d
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Projection From Top Of A Tower (EXPRESSION FOR HEIGHT OF TOWER): Consider a tower of height H. Suppose a body is projected upwards vertically with initial velocity from the top of tower. Sup
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Application-1: A balloon is rising up vertically. A stone is dropped from the balloon, when the velocity bal- loon is 'u'. At the instant, the stone velocity is also 'u' vertically
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Application-2: Three bodies are projected from towers of same height as shown. 1st one is projected vertically up with a velocity 'u'. The second one is thrown down vertically with the same
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Application-3 : A body projected vertically upwards from ground is at the same height h from the ground at two instants of time t1 and t2 (both being measured from the instant of projection) Now&nb
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Oblique Projectile From Inclined Surface OBLIQUE PROJECTILE Any body projected into the air at an angle other than 90° with the horizontal near the surface of the earth, is called a projectile
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THE TRAJECTORY OF PROJECTILE IS A PARABOLA (In absence of air resistance) In absence of air resistance) Let a body be projected at 'O' with an initial velocity u that makes an angle This
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2) Now let us consider the vertical motion. In vertical direction, the acceleration of the projectile is equal to the free fall acceleration which is constant and always directed downward &n
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MOTION PARAMETERS OF A PROJECTILE i) Time of ascent (ta) For a projectile the time to reach maximum height is called time of ascent. For a projectile, the vertical component of velocity vy , is z
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iii) Maximum height (Hmax): The vertical displacement of a projectile during time of ascent is the maximum height of the projectile. In the equation \( y = (u\sin \theta )t - \frac{1} {2}gt^2 \)
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v) Velocity of the Projectile at any Instant 't': The horizontal component of the projectile remains constant all the time. (because acceleration due to gravity has no component along the h
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important points: 1.The horizontal component of velocity remains constant all along. (since acceleration due to gravity has no component along the horizontal. 2.The vertical component of velocit
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7.If 'T' is the time of flight of a projectile, maximum height H=\( \frac{1} {8}gT^2 \) Sol. We know that , \( T = \frac{{2u\sin \theta }} {g} \Rightarrow u = \frac{{gT}} {{2\sin
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9. \( RTan\theta = 4{\rm H} = \frac{1} {2}gT^2 \) range of a projectile is maximum when angle of projection 45° , \( \therefore R = \frac{{u^2 \
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HORIZONTAL PROJECTILE Any body projected into the air at an angle other than 90° with the horizontal near the surface of the earth, is called a projectile. The science of projectile motion is
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HORIZONTAL PROJECTION FROM THE TOP OF A TOWER Equation for Path (Trajectory): Suppose a body is p
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MOTION PARAMETERS OF A HORIZONTAL PROJECTILE i) Time of Descent: It is the time the body takes to touch the ground after it is projected from the height 'h'. For y = h and t = t we get &
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iii) Velocity of the projectile at any time 't' Let the body be at point P after the time t. Let vx and vy be velocities along x and y-directions. The horizontal velocity remains constant
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Application-1 : If a body projected horizontally with velocity u from the top of a tower strikes the ground at an angle of 45°
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Application-3: A body is projected horizontally from the top of a tower. The line joining the point of projection and the striking point make an angle of 45° with the ground. Then, the displaceme
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Application-5 An aeroplane flies horizontally with a velocity 'u'. If a bomb is dropped by the pilot when the plane is at a height 'h' then a) the path of such as body is a vertical
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Application-8: Two bodies are thrown horizontally with velocities u1,u2 in mutually opposite directions from the same height. (or) A bomb at rest explodes into two fragments at a height 'h
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NEWTON’S LAWS OF MOTION Newton’s Laws of Motion : Newton’s First Law : Statement : "A body remains in a state of rest or of uniform motion unless acted uponby an external fo
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Consider the following example. A string with its one end connected to a ball and the other end held in hand is made to execute a circular motion. The string must providethe necessary centripetal for
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Newton’s Second law : Statement : The rate of change of momentum of a body is directly proportional to the external force and the change in momentum takes place in the direction of the
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NEWTON”S THIRC LAW:for every action there is an equal and opposite reaction. Examples: 1. Swimming. A swimmer pushes the water backwards (action).The water pushes the swimmer forward(re
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change of its linear momentum: Law of conservation of linear momentum: Collision: If a number of bodies collide with one another then total momentum of the bodies, just before collision
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change of its linear momentum: Law of conservation of linear momentum: Collision: If a number of bodies collide with one another then total momentum of the bodies, just before collision
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§§ APPLICATIONS OF THE PRINCIPLE OF CONSERVATION OF LINEAR MOMENTUM 1) Recoiling of a gun. When a bullet is fired from a gun, the gun recoils i.e. moves in a direction opposite to th
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2) Flight of rockets and jet planes. In rockets and jet planes,the fuel is burnt in the presence of some oxidising agent in combustion chamber. The hot and highly compressed gases escape through
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Dot Product DOT PRODUCT OR SCALAR PRODUCT In the previous chapters, we have studied vector quantities like displacement, velocity, acceleration, momentum, force etc. Addition and subtraction of ve
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PROPERTIES OF SCALAR PRODUCT a) The dot product between two vectors obeys commutative law i.e., \( \overrightarrow P .\overrightarrow Q = \overrightarrow Q .\overrightarrow P \) b) T
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Examples of scalar product: a) The scalar product of force and displacement, is called workdone by that force. i.e., \( W = \overrightarrow F .\overrightarrow S \) b)&n
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Application : Geometrically, \( Q\cos \theta \) is the projection of \( \overrightarrow Q \text{ }onto\text{ }\overrightarrow P \) and \( P\cos \theta \) is the projection o
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WORK INTRODUCTION: The terms ‘work’, ‘energy’ and ‘power’ are frequently used in everyday language. A farmer clearing weeds in his field is said to be working h
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TYPES OF WORKDONE:
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Zero work : Under three condition, work done becomes zero W=Fscos\(\theta\) = 0 (1) If the force is perpendicular to the displacement \( \l
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EXAMPLES: Examples of positive work done 1. Kicking a football 2. Moving a chair 3. Throwing a stone
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WORKDONE DUE TO CONSTANT FORCE Let a constant force \(\overrightarrow F\) be applied on the body such that it makes an angle \(\theta\) with the horizontal and body is displaced through
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Problem 1. A body of mass 5 kg is placed at the origin, and can move only on the x-axis. A force of 10 N is acting on it in a direction making an angle of 600 with the x-axis and displaces it al
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WORKDONE DUE TO VARIABLE FORCE: When the magnitude and direction of a force varies with position, the work done by such a force for an infinitesimal displacement is given by \( dW = \
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Problem 6. A position dependent force \( \overrightarrow F = \left( {7 - 2x + 3x^2 } \right)N \) acts on a small abject of mass 2 kg to displace it from x=0 to x=5m. The work done in joule is
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