Three identical polaroids P₁, P₂ and P₃ are placed one after another. The pass axis of P₂ and P₃ are inclined at an angle 60° and 90° with respect to axis of P₁. The source has an intensity I₀. The intensity of transmitted light through P₃ is (cos 60° = 0.5, cos 30° = √(3)/2) (a) I₀/8 (b) (3I₀)/(16) (c) (3I₀)/(32) (d) I₀/32

Answer: (c). After P₁: I₀/2; after P₂ ( 60°): I₀/2·1/4 = I₀/8 After P₃ ( 30° to P₂): I₀/8·3/4 = (3I₀)/(32) So the answer is (c) (3I₀)/(32).

Three identical polaroids P₁, P₂ and P₃ are placed one after another… | MHT CET 2024 (4 May, Shift 1)

Q31MHT CET 2024 · 4 MAY · SHIFT 1Medium

Polarisation

Three identical polaroids $P_1, P_2$ and $P_3$ are placed one after another. The pass axis of $P_2$ and $P_3$ are inclined at an angle $60^\circ$ and $90^\circ$ with respect to axis of $P_1$ . The source has an intensity $I_0$ . The intensity of transmitted light through $P_3$ is $\left(\cos 60^\circ = 0.5, \cos 30^\circ = \frac{\sqrt{3}}{2}\right)$

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Answer: (c)

After $P_1$ : $I_0/2$ ; after $P_2$ ( $60^\circ$ ): $\frac{I_0}{2}\cdot\frac{1}{4} = \frac{I_0}{8}$
After $P_3$ ( $30^\circ$ to $P_2$ ): $\frac{I_0}{8}\cdot\frac{3}{4} = \frac{3I_0}{32}$
So the answer is (c) $\frac{3I_0}{32}$ .

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Polarisation question from MHT CET 2024 (4 May, Shift 1)

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