JEE Main 2021PhysicsWaves and SoundHardNumerical

JEE Main 2021 — Waves and Sound Question with Solution

JEE Main 2021 (18 Mar Shift 2)

Question

A galaxy is moving away from the earth at a speed of 286 km s-1. The shift in the wavelength of a red line at 630 nm is x×10-10 m. The value of x, to the nearest integer, is ___ .

[Take the value of the speed of the light c, as 3×108 m s-1]

Enter your answer

Show full solutionCorrect answer: 6
Correct answer
6

Step-by-step explanation

⇒Δλλc=v, 

⇒Δλ=vc×λ=2863×105×630×10-9=6×10-10 m

Practice this on the real CBT interface

Solve this JEE Main question (and the rest of the Waves and Sound chapter) on PrepSharp's TCS iON-style CBT player — with timer, bookmarks and session analytics.

Solve interactively →

About this question

This is a previous-year question from JEE Main 2021, covering the Waves and Sound 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.