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Saturday, 31 October

JEE Main 2021 · PhysicsNumerical answerNumerical valueEasyCalculation

JEE Main 18 March 2021, Shift 2, Physics Q27

Question 27 of 90 in this shift, Physics question 27 of 30, Section B.

A galaxy is moving away from the earth at a speed of 286 kms−1^{-1}. The shift in the wavelength of a redline at 630 nm is x×10−10x\times10^{-10} m. The value of xx, to the nearest integer, is _________. [Take the value of speed of light c, as 3×1083\times10^8 ms−1^{-1}]

Official answer

6

NTA final key.

Chapter
Waves
Topic
Doppler Effect
Idea tested
Light Doppler Approximation

Same idea in other shifts

Asked 2× in all
  1. 26 Jun 2022, Shift 2 · Q46For a specific wavelength 670 nm of light coming from a galaxy moving with velocity vv, the observed wavelength is 670.7 nm. The value of…EasySingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.