JEE Main 2017PhysicsWave OpticsMediumMCQ

JEE Main 2017 — Wave Optics Question with Solution

JEE Main 2017 (08 Apr Online)

Question

A single slit of width b is illuminated by a coherent monochromatic light of wavelength λ. If the second and fourth minima in the diffraction pattern at a distance 1 cm from the slit are at 3 cm and 6 cm respectively from the central maximum, what is the width of the central maximum? (i.e. distance between first minimum on either side of the central maximum)

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Show full solutionCorrect option: D
Correct answer
D3.0 cm

Step-by-step explanation

For secondary minima dsin⁡θ=nλ
sin⁡θ=nλd

For second minima
n=2
sin⁡θ=2λd=tan⁡θ1=x1D
For fourth minima n=4
sin⁡θ2=4λd=x2D

Distance between both minima is x2-x1=4λd-2λd=2λd= 6 -3 =3 cm

Width of central maxima,=2λd=3 cm

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About this question

This is a previous-year question from JEE Main 2017, 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.