Two polaroids P₁ and P₂ are placed with their axes perpendicular to each other. Unpolarised light I₀ is incident on P₁. A third polaroid P₃ is kept between P₁ and P₂ with its axis making 45° with that of P₁. The intensity transmitted through P₂ is:
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Question

Two polaroids P₁ and P₂ are placed with their axes perpendicular to each other. Unpolarised light I₀ is incident on P₁. A third polaroid P₃ is kept between P₁ and P₂ with its axis making 45° with that of P₁. The intensity transmitted through P₂ is:

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G1 Physics · Accepted Answer

Step 1: After P₁, intensity I₁ = I₀/2. Step 2: P₃ makes 45° with P₁: I₂ = I₁ cos²45° = I₀/4. Step 3: P₂ is perpendicular to P₁, so angle between P₃ and P₂ is 45°: I₃ = I₂ cos²45° = I₀/8. Final answer: (C) I₀/8.