Question

In which order, the colour spectrum VIBGYOR appeared to us in the rainbow:
A) Top to bottom.
B) Bottom to top.
C) Left to right.
D) Right to left.

Answer 1

Hint: Total internal reflection is the phenomenon in which the light passes from the denser to lesser medium and the angle of incidence exceeds the critical angle and due to which the and due to which the light gets back to the same medium.

Complete solution:
It is asked in the problem about the sequence of the colour spectrum VIBGYOR that appears in rainbow. The rainbow is an optical phenomenon which takes place due to the reflection, refraction and dispersion.
When the sunlight comes and hits the water droplet then the refraction takes place and as the light travelling from rare to denser medium therefore the speed of light slows and the light bends towards the normal. Now it hits the interface of the water droplet again but the angle of incidence is more than critical angle and therefore total internal reflection takes place due to which the light again gets back to the water droplet medium and the again the light tries to escape the droplet as the angle of incidence is less than the critical angle and therefore the light comes out of the water droplet and the dispersion phenomenon takes place which forms the colour spectrum and the sequence is VIBGYOR.
The sequence of the colour spectrum is from the left to right.

The correct answer for this problem is option C.

Note: The total internal reflection is the phenomenon due to which we can see rainbows. The spectrum of rainbow is made by decreasing frequency and increasing wavelength, the least wavelength is of the violet and the maximum wavelength is red colour.