JEE Main 2019PhysicsWave OpticsMediumMCQ

JEE Main 2019 — Wave Optics Question with Solution

JEE Main 2019 (12 Apr Shift 1)

Question

In a double slit experiment, when a thin film of thickness t having refractive index μ is introuduced in front of one of the slits, the maximum at the centre of the fringe pattern shifts by one fringe width. The value of t is (λ is the wavelength of the light used):

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Show full solutionCorrect option: D
Correct answer
Dλ(μ-1)

Step-by-step explanation

Shift =μ-1 tDd
Fringe width (β)=λDd
(μ-1)  tDd=λDd
t=λμ-1

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About this question

This is a previous-year question from JEE Main 2019, 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.