Why A Rainbow Is Formed
A rainbow is a natural phenomenon in which the white light of the sun is scattered by water droplets in the atmosphere. You can see a rainbow in the sky when the sun shines through the rain. This is the only event where light refraction, scattering and reflection occur at one time.
But do you know that there are two kinds of rainbow?
The two kinds of rainbow are the followings:
- The primary or main rainbow
- The secondary rainbow
What is a primary rainbow and how is it formed?
In the first step, a ray of the sun is refracted on the surface of a droplet. Then the ray is reflected on the back inside it. After that, the ray again becomes refracted while leaving the droplet. And finally a primary rainbow is formed that appears to be part of a circular arc from the Earth’s surface to a viewer with red on the outside and purple on the inside.
What is a secondary rainbow and how is it formed?
While entering inside the droplet, a ray of the sun becomes refracted and then it is reflected two times inside it. After that, it is refracted while leaving the droplet. In this case, the light is reflected twice in the water particle. So, the brightness of the secondary rainbow is less than that of the primary rainbow. The order of colors in the secondary rainbow is exactly the opposite of the primary rainbow. The secondary rainbow has red on the inside and purple on the outside.