Question

Unpolarized light of intensity $I_0$ is incident on a set of $3$ polaroids as shown. The pass axis of each polaroid is perpendicular to direction of propagation. One of the polaroid is rotated about the common direction of propagation of light.

• A. If A is rotated, the final intensity remain unchanged.
• B. If B is rotated, the final intensity will change.
• C. If B is rotated, the final intensity remains unchanged.
• D. If C is rotated, the final intensity remains unchanged.

Answer 1

The correct option is B If B is rotated, the final intensity will change.

The intensity of light defend upon Angular diff between the axies of pdaroid

$I=I_o{\cos }^2\theta$

where $\theta =$ angle between axies of pdaroi

So If we rotate $B$ then angle between axies of $(A,B)$ and $(B,C)$ both changed we get final intensity changed