A light ray passes from air through a thin plastic slab (n = 1.77)with parallel sides.If the ray in air makes an angle of 49° with the normal after leaving the slab,what is the angle of incidence for the ray in air as it impinges upon the other side of the slab?
A)25°
B)49°
C)14°
D)28°
E)87°

Question

A light ray passes from air through a thin plastic slab (n = 1.77)with parallel sides.If the ray in air makes an angle of 49° with the normal after leaving the slab,what is the angle of incidence for the ray in air as it impinges upon the other side of the slab?
A)25°
B)49°
C)14°
D)28°
E)​87°

Quizplus · Accepted Answer

The angle of incidence in air equals the angle of emergence due to the parallel sides of the slab and the principle of reversibility of light.

A Light Ray Passes from Air Through a Thin Plastic