JEE Main 2022PhysicsWave OpticsEasyNumerical

JEE Main 2022 — Wave Optics Question with Solution

JEE Main 2022 (28 Jul Shift 1)

Question

In a Young's double slit experiment, a laser light of 560 nm produces an interference pattern with consecutive bright fringes' separation of 7.2 mm. Now another light is used to produce an interference pattern with consecutive bright fringes' separation of 8.1 mm. The wavelength of second light is _____ nm.

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Show full solutionCorrect answer: 630
Correct answer
630

Step-by-step explanation

Given here: λ1=560×10-9 m, β1=7.2×10-3 m and β2=8.1×10-3 m.

Let d be the width and D be the distance between slit and screen then fringe width, β=λDd.

Thus, from above,  β∝λ

So, the wavelength of second light is λ2=β2β1λ1=98λ1

∴   λ2=98×560=630 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.