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Question 20220
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Electromagnetic Waves and Wave Optics: Polarisation — Malus's Law MCQ

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Polarisation — Malus's LawEasyQuestion 20220

Question

A beam of plane polarised light (intensity I₀) passes through an analyser at angle θ to the polariser axis. Transmitted intensity is:
  1. A
    I₀ cosθ
  2. B
    I₀ cos²θ
    Correct
  3. C
    I₀ sinθ
  4. D
    I₀/2 regardless of angle

Correct answer

I₀ cos²θ

Explanation

Malus's law: I = I₀ cos²θ. At θ = 0° (analyser parallel to polariser): I = I₀ (full transmission). At θ = 90°: I = 0 (complete extinction).

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