JEE Main 2020PhysicsWaves and SoundMediumMCQ

JEE Main 2020 — Waves and Sound Question with Solution

JEE Main 2020 (09 Jan Shift 2)

Question

A wire of length L and mass per unit length 6.0×10-3 kg m-1 is put under tension of 540 N. Two consecutive frequencies that it resonates at are: 420 Hz and 490 Hz. Then L in meters is :

Choose an option

Show full solutionCorrect option: A
Correct answer
A2.1m

Step-by-step explanation

Fundamental frequency =490-420=70 Hz
70=12LTμ
⇒70=12L5406×10-3
⇒L=12×7090×103=300140
⇒L≈2.14 m

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About this question

This is a previous-year question from JEE Main 2020, 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.