Question

Unpolarized light of intensity $I_0$ is incident on a polarizer and the emerging light strikes a second polarizing filter with its axis at 45$^\circ$ to that of the first. The intensity of the emerging beam

• A. $\frac{I_0}{2}$
• B. $\frac{I_0}{4}$
• C. $\frac{I_0}{1}$
• D. $\frac{I_0}{3}$

Answer 1

Answer: (B)

$\frac{I_0}{4}$

Answer 2

$I = \frac{I_0}{2} \, I_2 = \frac{I_0}{2} cos^2 \, \theta$