Question

a light ray can minimize time to travel between two points only when it's _______ changes at interface between two media​

Answer 1

Answer:

how is light ray refracted if it is incident normally to the interface of two media? It will propagate in same direction as incident ray of light. ... So, all the parts of light will have a change in speed at the same time. So, there will be no bending but only change in speed of light ray.