Light is incident at the Brewster angle on a plastic plate in air.The angle of refraction is 35.0°.
-What is the index of refraction of the plastic plate?
A)1.58
B)1.36
C)1.43
D)1.61
E)1.74

Question

Quizplus · Accepted Answer

Brewster's law states that when light is incident at the Brewster angle, the reflected light is completely polarized and the reflected and refracted rays are perpendicular to each other. 
tanθB=n, where θB is the Brewster angle and n is the index of refraction of the medium.
Thus, n=tanθB= tan35.0°=1.43 (rounded to two decimal places).

Light Is Incident at the Brewster Angle on a Plastic