Question

The refractive indices of three media are given below:

Medium	Refractive Index
A	1.6
B	1.8
C	1.5

A ray of light is travelling from A to B and another ray is travelling from B to C.

1. In which of the two cases the refracted ray bends towards the normal?
2. In which case does the speed of light increase in the second medium?

Give reasons for your answer.

Answer 1

1. When light travels from an optically rarer medium to an optically denser medium it moves towards the normal. Since n_B > n_A hence the light ray will bend towards the normal on passing from medium A to B.
2. The speed of the light will increase when the light travels from B to C, Since n_C < n_B and v = (c/n), the speed of the light ray will increase in the second medium.