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Question 20206
JEE Physics · Medium

Electromagnetic Waves and Wave Optics: Intensity in Interference MCQ

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Intensity in InterferenceMediumQuestion 20206

Question

If two coherent sources have intensities I₀ each, the maximum intensity at a bright fringe is:
  1. A
    I₀
  2. B
    2I₀
  3. C
    4I₀
    Correct
  4. D
    √2 I₀

Correct answer

4I₀

Explanation

Amplitude adds: A_max = A₁ + A₂ = 2A (when amplitudes are equal). Intensity ∝ A²: I_max = (2A)² = 4A² = 4I₀. Minimum intensity = (A₁ − A₂)² = 0 (for equal amplitudes).

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