Question

The change in speed (Q. 1) causes a change in the direction of the light ray. What change is observed when light goes from: a. air to water b. water to air?

Answer 1

(a) When a light ray travels from air into water, it's speed decreases. So, it bends towards the normal to the interface between the water and the air.

(b) When a light ray travels from water into the air, it's speed increases. So, it bends away from the normal to the interface between the water and the air.