As shown in the figure, 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 angle of 60 ° and 90 ° with respect to axis of P 1. The source S has an intensity of 256 W/m². The intensity of light at point O is ____________ W/m². Numerical answer type. Work it out, then open the answer.

Answer: 24. After P₁: 256/2 = 128 W/m² After P₂ ( 60° to P₁): 128 × 1/4 = 32 W/m² After P₃ ( 30° to P₂): 32 × 3/4 = 24 W/m² So the intensity at O is 24 W/m².

As shown in the figure, three identical polaroids P 1, P 2 and P 3… | JEE Main 2023 (29 Jan, Shift 1)

Q36JEE Main 2023 · 29 JAN · SHIFT 1Medium

Polarisation

As shown in the figure, 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 angle of 60 ${}^\circ$ and 90 ${}^\circ$ with respect to axis of P $1$ . The source S has an intensity of 256 $\frac{W}{m^2}$ . The intensity of light at point O is ____________ $\frac{W}{m^2}$ .

Numerical answer type. Work it out, then open the answer.

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Answer: 24

After $P_1$ : $\frac{256}{2} = 128\ \text{W/m}^2$
After $P_2$ ( $60^\circ$ to $P_1$ ): $128 \times \frac{1}{4} = 32\ \text{W/m}^2$
After $P_3$ ( $30^\circ$ to $P_2$ ): $32 \times \frac{3}{4} = 24\ \text{W/m}^2$
So the intensity at O is $24\ \text{W/m}^2$ .

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Polarisation question from JEE Main 2023 (29 Jan, Shift 1)

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