Question

if the glass slab is of the following shape and the experiment is performed as above will the effects be the same ? here s1 and s2 are slab surfaces parallel to each other

Answer 1

In a glass slab opposite sides are parallel. The angle of refraction becomes the angle of incidence in the second face. The emergent ray bends in such a way that the angle of incidence becomes the angle of emergence. In this case the incident ray and the emergent ray will not be parallel to each other

Answer 2

"When a light ray enters at an angle (oblique) and strikes at the interface point of two optical media, the direction of the path of the light ray changes when it enters one medium to another.

When a "ray of light" passes through a glass slab, it changes its direction due to refraction of light. The incident light ray (i) gets laterally displaced and "bends towards the normal" (n) when it enters from the rarer air medium to the denser glass medium.

When the emergent light ray (e) emerges out from the denser glass medium to the lighter air medium then it moves "away from the normal". In a "parallel-sided glass" slab, the direction of incident light ray (i) is parallel and equal to the direction of the emergent light ray (e) because the two interface surfaces of the glass slab are parallel and equal to each other.

Fig: Refraction of "light" through a "parallel-sided glass" slab."