Plane polarized light is sent through two consecutive polarizers, the first having its plane of polarization in the same direction as the incident light and the second having its plane at 90° to the original plane of polarization. A third polarizer, with plane of polarization at 60° to the original plane of polarization, is placed between the two other polarizers. What fraction of the original intensity now gets through?
A) 0.56
B) 0.19
C) 0
D) 0.25

Question

Quizplus · Accepted Answer

When the third polarizer is added at 60°, the intensity after the first polarizer is unchanged. After the second polarizer (60°), the intensity is reduced by cos²(60°) = 0.25. After the third polarizer (90°), the intensity is further reduced by cos²(30°) = 0.75. Thus, the final intensity is 0.25 * 0.75 = 0.1875, approximately 0.19.

Plane Polarized Light Is Sent Through Two Consecutive Polarizers, the First