What is Light?#!#Sources of Light

What is a point source of light?

What are coherent sources of light ? Why are coherent sources required to obtain sustained interference pattern ?

For steady interference of light, the two sources of light must be

Examples of hot source of light

IF Young's experiment is performed using two separate identical sources of light instead of using two slits and one light source then the

What are cold and hot sources of light? Give examples for each.

Two inependent monochromatic sources of light are