Question

give an explanation for the formation of a rainbow.

Answer 1

By dispersion of the light.

Answer 2

Here's ur answer ,

FORMATION OF RAINBOW :

1) The formation of rainbow in sky is a combined result of refraction , dispersion and reflection of Sunlight by water droplets present in the atmosphere after it has rained.

2) The sunlight is a mixture of seven colours : violet ,Indigo, blue,green,yellow,orange and red . After , it has stopped rained, the atmosphere contains large number of water droplets. When the sun light is incident on a water droplet there is ,
( a )refraction and Dispersion of light as it passes from air to water
( b) internal reflection of light inside the droplet and
( c) refraction of light as it passes from water to air.

3) The refractive index of water is different for different colours, wheel maximum for violet and minimum for red.Hence ,there is Dispersion of light (separation into different colours )as it passes from air to water .

4) The combined action of different water droplets ,acting like tiny prisms, is to produce Rainbow with red colour at outer side and violet colour at innocent the remaining 5 colours live between these two.

The Rainbow scene when the sun is behind the observer and water droplets is in the front.


See the diagram for reference.

Hope it helps you!