Question

A ray of light travelling in medium I, strikes medium II at angle (not zero or more than 90°) and passes out of it without any change of direction. What can you say about the refractive indices of the medium I and II? Explain.

Answer 1

The refractive indices of media I and II are equal. Since the ray is incident obliquely but does not change direction, the angle of refraction equals the angle of incidence. By Snell’s law, n_I sin i = n_II sin r, with i = r, it follows that n_I = n_II. Thus, the two media are optically equivalent for the ray.