Question

I thought answer is C but it is A. Why is that so? And what does opposite side mean?

Answer 1

A.

Explanation:

The ray of light enters the spherical water drop from right to left.
The emergent ray of light when viewed from opposite side, means viewed from left side of water drop looking towards right.

The interface is defined by tangent at the point of incidence. Consequently normal at the point of incidence will coincide with the direction of the ray of light.
This means that angle of incidence`=0^@`. For this angle, the ray will pass the water drop without deviation, through centre C, and hit the opposite side of water drop.

Here we observe again that normal at the point of incidence within the water drop, on the other side, is parallel to the direction of travel of ray of light. This implies that angle of incidence is `0^@`. Therefore, the ray of light emerges out of the water drop without deviation.

When observed from the opposite side it will remain un-deviated and white as neither there is any refraction nor dispersion.