A beam of light in air is incident at an angle of 30 $\degree$ to the surface of a rectangular block of clear plastic (n = 1.46).The light beam first passes through the block and re-emerges from the opposite side into air at what angle to the normal to that surface?
A)42 $\degree$
B)23 $\degree$
C)30 $\degree$
D)59 $\degree$

Question

Quizplus · Accepted Answer

According to Snell's Law, the angle of incidence equals the angle of emergence when light passes through a parallel-sided medium like a rectangular block. Thus, the light re-emerges at the same angle of 30° to the normal.

A Beam of Light in Air Is Incident at an Angle