The diagram below shows two parallel rays A and B of red and violet light respectively incident from air on air-glass boundary. Complete the diagram showing the refracted rays for them in the glass.

(i) How do the speeds of the rays differ in glass ?
(ii) are the two refracted rays in glass parallel ?
Give a reason for your answer.
(iii) How does the refractive index of glass differ for the two rays ?

Explanation

The completed ray diagram is shown below in figure.

(i) In glass, the speed of violet light is less than that of the red light.
(ii) The two refracted rays inside glass are not parallel. The reason is that the speed of red light in glass is more, while it is less for the violet light, so the red ray bends less, while the violet ray bends more (i.e., the angle of refraction `r_(1)` for red ray is more than the angle of refraction `r_(2)` for the violet ray).
(iii) Since `mu=c//V`, so the refractive index of glass is more for the violet light than for the red light (i.e., `mu_(V) gt mu_(R)`).