Question

define primary rainbow and secondary rainbow.

what is the order of colours in primary rainbow and secondary rainbow?

Answer 1

We know that the rainbow is formed 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. The order of colours is violet, Indigo,Blue, Green, Yellow, Orange and Red.
In a primary rainbow the sunlight is internally reflected once while in a secondary rainbow the sunlight is internally reflected twice. Also, the secondary rainbow is a lot less intense and forms at a separation of about 10 degrees from the primary rainbow.
In case of primary rainbow, the outer arc is red and inner arc is violet whereas in secondary rainbow, the outer arc is violet and inner arc is red.