A polaroid sheet $P_2$ is rotated by an angle θ (angle between pass axies of $P_1$ and $P_2$) between two crossed polaroids $P_1$ and $P_3$. The intensity of transmitted light will be maximum for:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → $θ=45°$
The intensity of transmitted light through two polaroids is governed by Maul's law.
$I=I_0\cos^2(θ)$
where,
$I_0$ = Intensity of light incident on polarizer.
θ = Angle between light's polarization direction and axis of polarizer.
Given,
- $P_1,P_2,P_3$ are 3 polaroids.
- pass axis of $P_1$ is aligned in a particular direction and the pass axis of $P_2$ is rotated by an angle θ relative to $P_1$.
- pass axis of $P_3$ is perpendicular to $P_1$
for maximum intensity to be transmitted through $P_3$ the angle between the pass axiz of $P_2$ and $P_3$ must be zero. Since $P_1$ and $P_3$ are crossed (90° to each other).
The condition will be satisfied when the angle between $P_1$ and $P_2$ is 45°.