Question

what happens to the speed of light when it enters from air into the glass through the normal?​

Answer 1

Answer:When light rays travel from air into glass or from air into water, it bends towards normal. This is because the speed of light rays decrease while travelling from air into glass or water. Case 2: When light rays travel from optically denser medium to rarer medium then they bend away from the normal.

Answer 2

What happens is that light slows down when it passes from the less dense air into the denser glass or water. This slowing down of the ray of light also causes the ray of light to change direction. It is the change in the speed of the light that causes refraction.