With the necessary figure, explain the refraction of light through a rectangular glass slab.

Consider the rectangular slab as shown in the figure below.

AE = incident ray;

i = Angle if incidence;

r = Angle of refraction;

On entering the glass slab the light ray bends towards the normal and travels along EF.

The refracted ray EF is incident on the face SR at angle of incidence r’.

The emergent ray FD bends away from normal at angle of refraction e.

The emergent ray FD is parallel to the incident ray AE but it has been laterally displaced with respect to incident ray.