i. A ray AB incident from Sun (white light) strikes the lower portion of a water drop at an incident angle i.
ii. On entering into water, it deviates and disperses into constituent colours. The figure shows the extreme colours (violet and red).
iii. Refracted rays BV and BR finally emerge the drop from V’ and R’ after suffering two internal reflections and can be seen by an observer on the ground.
iv. Minimum deviation rays of red and violet colour are inclined to the ground level at θR ≈ 51° and θV ≈ 53° respectively. As a result, in the rainbow, the violet is above and red is below.
