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Question
In Young's double-slit experiment, the separation between the two slits is d and the distance of the screen from the slits is 1000 d. If the first minima fall at a distance d from the central maximum, obtain the relation between d and λ.
Solution
In Young's double-slit experiment, the separation between two slits is d.
Distance of the screen from the slit D = 1000 d
By using Bragg's law,
nλ = 2D sinθ
⇒ n = 1, D = 1000 d
⇒ 1 × λ = 2 × 1000 d sinθ
⇒ λ = 2000 d sinθ
d = `lambda/2000sintheta`
Hence, the relation between d and λ is `d = lambda/2000sintheta`.
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