Q. Two Polaroids $P_1$ and $P_2$ are placed with their axis perpendicular to each other. Unpolarised light $I_0$ is incident on $P_1$. A third polaroid $P_3$ is kept in between $P_1$ and $P_2$ such that its axis makes an angle 45° with that of $P_1$. The intensity of transmitted light through $P_2$ is :
A) $\frac{I_0}{2}$
B) $\frac{I_0}{4}$
C) $\frac{I_0}{8}$
D) $\frac{I_0}{16}$
Explanation
[Solution] $I = \frac{I_0}{2}\cos^2 45^\circ \cos^2 45^\circ = \frac{I_0}{8}$. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.