Question

"Rainbow is an example of dispersion of sunlight." Justify this statement by explaining, with the help of a labelled diagram, the formation of a rainbow in the sky. List two essential conditions for observing a rainbow.

Answer 1

rainbow is formed by the dispersion of white light. the conditions for the rainbow to be observed is the sun should be at the back of the observer .
every rain drop acts like a prism, so when sunlight falls on the rain drop first it refracts and disperses into seven colours and then internally reflects and finally refracts and comes out of the rain drop in the form of a rainbow.

Answer 2

Rainbow forms when sunlight hits the water droplets suspended in the atmosphere and undergoes total internal reflection. When the sunlight comes out of the drop it disperses, where the drop acts like a small prism. This dispersion or breaking up of light into several colors is what forms the rainbow. Hence, rainbow is an example of dispersion of sunlight.

Conditions for rainbow formation are:

1. A rain shower must have occurred  so that there is enough moisture in atmosphere.

2. The sun should be in the opposite direction.