JEE Main 2021 — Wave Optics Question with Solution
From: JEE Main 2021 (Online) 18th March Evening Shift
Question
A galaxy is moving away from the earth at a speed of 286 kms1. The shift in the wavelength of a redline at 630 nm is x 1010 m. The value of x, to the nearest integer, is ____________. [Take the value of speed of light c, as 3 108 ms1]
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Show full solutionCorrect answer: 6
Correct answer
6
Step-by-step explanation
From Doppler effect, we know
here, m/s
m/s
= 6 1010 m
here, m/s
m/s
= 6 1010 m
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This is a previous-year question from JEE Main 2021, 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.