Unpolarized light of intensity 32 Wm passes through three polarizers such that transmission axis -2 of the first and second polarizer makes an angle of 30° with each other and the transmission axis of the last polarizer is crossed with that of the first. The intensity of final emerging light will be
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Question

Unpolarized light of intensity 32 Wm passes through three polarizers such that transmission axis -2 of the first and second polarizer makes an angle of 30° with each other and the transmission axis of the last polarizer is crossed with that of the first. The intensity of final emerging light will be

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G1 Physics · Accepted Answer

After the first polarizer, intensity is 16 W m⁻². Through the second at 30°: 16cos²30°=12. The third is at 90° to the first, hence 60° to the second: 12cos²60°=3 W m⁻². Hence option B.