Q 12-10-146JEE MainJEE Main 2019 (12 Apr, Shift 2)Easy
A system of three polarizers $P_1$, $P_2$, $P_3$ is set up such that the pass axis of $P_3$ is crossed with respect to that of $P_1$. The pass axis of $P_2$ is inclined at $60^\circ$ to the pass axis of $P_3$. When a beam of unpolarized light of intensity $I_0$ is incident on $P_1$, the intensity of light transmitted by the three polarizers is $I$. The ratio $(I_0/I)$ equals (nearly):
Answer: (D) $10.67$
$P_2$ is at $30^\circ$ to $P_1$ and $60^\circ$ to $P_3$:
$$I = \frac{I_0}{2}\cos^230^\circ\cos^260^\circ = \frac{I_0}{2}\times\frac34\times\frac14 = \frac{3I_0}{32}$$
$$\frac{I_0}{I} = \frac{32}{3} \approx 10.67$$
Solution by Sreeraj P, M.Sc Physics