NEET 2025 · PhysicsPrevious Year Question
A polaroid sheet is placed between two crossed polaroids, with its polarization axis at 22.5° from the polarization axis of one of the polaroids. The intensity of the transmitted light is (I₀ is the intensity of polarized light after passing through the first polaroid)
- A.I₀/8✓
- B.I₀/16
- C.I₀/2
- D.I₀/4
Correct Answer
(A) I₀/8
Solution & Explanation
Answer: (A) I₀/8. Solution: After the first polaroid the intensity is I₀. The middle sheet at 22.5°: I₀cos²22.5°. The last polaroid is at 90° − 22.5° = 67.5° from the middle: I = I₀cos²22.5°cos²67.5° = I₀(cos22.5°·sin22.5°)² = I₀(½sin45°)² = I₀(√2/4)² = I₀/8.
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