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Question: Answered & Verified by Expert
The angular width of the central maximum in a single slit diffraction pattern is 60° . The width of the slit is 1 μm. The slit is illuminated by monochromatic plane waves. If another slit of the same width is made near it, Young's fringes can be observed on a screen placed at a distance 50cm from the slits. If the observed fringe width is 1cm, what is slit separation distance? (i.e. the distance between the centres of each slit.)
PhysicsWave OpticsNEET
Options:
  • A 100 μm
  • B 25 μm
  • C 50 μm
  • D 75 μm
Solution:
1096 Upvotes Verified Answer
The correct answer is: 25 μm
In diffraction

dsin30°=λ

λ=d2



Young’s fringe width [ d'-the separation between two slits ] 

β=λ×Dd'

10-2=d2×50×10-2d'

10-2=10-6×50×10-22×d'

d'=25 μm

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