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NEET 1993 (AIPMT) · Diffraction at a Single Slit

Diffraction at a Single Slit question from NEET 1993 (AIPMT)

Q87NEET 1993 · AIPMTEasy

Diffraction at a Single Slit

A parallel beam of monochromatic light of wavelength 5000 Å is incident normally on a single narrow slit of width 0.001 mm. The light is focussed by a convex lens on a screen placed in focal plane. The first minimum will be formed for the angle of diffraction equal to

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Answer: (c)

  1. First minimum: sin⁡θ=λa\sin\theta = \frac{\lambda}{a}.
  2. sin⁡θ=5×10−71×10−6=0.5⇒θ=30∘\sin\theta = \frac{5\times10^{-7}}{1\times10^{-6}} = 0.5 \Rightarrow \theta = 30^\circ.
  3. So the answer is (c) 30∘30^\circ.
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