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MHT CET 2026 (20 Apr, Shift 1) · Diffraction at a Single Slit

Diffraction at a Single Slit question from MHT CET 2026 (20 Apr, Shift 1)

Q11MHT CET 2026 · 20 APR · SHIFT 1Medium

Diffraction at a Single Slit

Light of wavelength 580580 nm is incident normally on a slit of width 'aa'. The distance between slit and screen is 2.52.5 m and the distance of the second order maximum from the centre of the screen is 14.514.5 mm in a diffraction pattern. The value of 'aa' is

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Answer: (b)

  1. nnth secondary maximum: yn=(2n+1)λD2ay_n = \dfrac{(2n+1)\lambda D}{2a}; for n=2n = 2, y=5λD2ay = \dfrac{5\lambda D}{2a}
  2. a=5λD2y=5×580×10−9×2.52×14.5×10−3a = \dfrac{5\lambda D}{2y} = \dfrac{5 \times 580 \times 10^{-9} \times 2.5}{2 \times 14.5 \times 10^{-3}}
  3. a=0.25×10−3a = 0.25 \times 10^{-3} m. So the answer is (b).
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