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Problem 10 - Olympiad

In a single-slit diffraction pattern the angular width of the central maximum is 30° for λ = 600 nm. The slit width is

Correct: B

First minimum: a sinθ = λ. Central width 2θ = 30° → θ = 15°. a = λ/sin15° ≈ 600 nm/0.2588 ≈ 2.3 µm → 2.4 µm.