Light

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 vision is called optics.
3.Light is a form of energy which is propogated as electromagnetic waves.
4.It does not require a medium for its propogation.
5.Its speed in free space is 3 x 10⁸ m/s. It is transverse in nature. It is not deflected by electric and magnetic fields.
6.When light meets a surface which seperates two media, reflection and refraction take place. An image or an array of images may be formed due to intersection of reflection or refracted rays.

¶¶ Light: It is an invisible energy which causes us sensation of sight (vision).
            

¶¶ Sources of light: Sun is the primary source of light.

¶¶ Luminous bodies: The bodies which gives out light energy by themselves are called luminous bodies.
Ex: sun, stars, burning candle, glowing electric bulb, glow warm etc.
         
¶¶ Non-Luminous bodies: 
The bodies which do not give light energy of their own, but reflect
light energy falling on them are called non-luminous bodies.
Ex: wood, house, moon, furniture etc.
Speed of light is 3 x 10⁸m/s (or) 3,00,000km/s (or) 3X10¹⁰cm/s (or) 3 X 10¹¹mm/s