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Two crossed polaroids transmit light of intensity:

AI₀ (full intensity)
BZero — because cos²(90°) = 0; no light gets through
CI₀/2
DI₀/4
Answer & Solution
Correct answer: B. Zero — because cos²(90°) = 0; no light gets through
**Crossed polaroids (pass-axes at 90°)**: I_transmitted = I_polarised × cos²(90°) = **0**. Complete extinction. This is the basis of polarimeters and 3D glasses (where each lens passes only one polarisation).
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