Question

State two conditions under which a ray of light suffering refraction from medium 1 to medium 2 does not undergo any change in direction

Answer 1

1) When the incident ray makes an angle 90 with the interface.
2) When the refractive index of both the medium is equal.

Answer 2

If there is no direction change , there is no refraction. that's what refraction is

Explanation:

when a ray of light travels from medium 1 to medium 2 without any change of direction. it is possible under either of the following two conditions :

(i) a ray of light is incident normally on the surface separating two media.

(ii) The refractive index of medium 1 is equal to the refractive index of medium 2.