JEE Main 2022PhysicsWave OpticsEasyNumerical

JEE Main 2022 — Wave Optics Question with Solution

JEE Main 2022 (27 Jun Shift 1)

Question

In Young's double slit experiment the two slits are 0.6 mm distance apart. Interference pattern is observed on a screen at a distance 80 cm from the slits. The first dark fringe is observed on the screen directly opposite to one of the slits. The wavelength of light will be _____ nm.

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Show full solutionCorrect answer: 450
Correct answer
450

Step-by-step explanation

According to the question, the first dark fringe is observed directly opposite to one of the slits. Therefore, half of the fringe width is equal to half of the distance between the slits.

β2=d2⇒β=d=6 mm

⇒λDd=0.6×10-3⇒ λ=0.6×10-3dD⇒ λ=0.6×10-3×0.6×10-380×10-2

⇒λ=450×10-9 m=450 nm

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About this question

This is a previous-year question from JEE Main 2022, covering the Wave Optics chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.