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Physics · PYQ NEET UG 2017
हिन्दीTwo 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 \( 45^\circ \) with that of \( P_1 \). The intensity of transmitted light through \( P_2 \) is:
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Correct answer · Option B
\( \frac{I_0}{8} \)
Explanation
After \( P_1 \), intensity is \( \frac{I_0}{2} \). After \( P_3 \) at \( 45^\circ \), intensity is \( \frac{I_0}{2} \cos^2(45^\circ) = \frac{I_0}{4} \). After \( P_2 \) at \( 45^\circ \) to \( P_3 \), intensity is \( \frac{I_0}{4} \cos^2(45^\circ) = \frac{I_0}{8} \).
