JEE Main 2021PhysicsOscillationsHardMCQ

JEE Main 2021Oscillations Question with Solution

JEE Main 2021 (27 Jul Shift 1)

Question

Two identical tennis balls each having mass m and charge q are suspended from a fixed point by threads of length l. What is the equilibrium separation when each thread makes a small angle θ with the vertical?

Choose an option

Show full solutionCorrect option: B
Correct answer
Bx=q2l2πε0mg13

Step-by-step explanation

Tcosθ=mg
Tsinθ=kq2x2
tanθ=kq2x2mg
as tanθsinθx2L
x2L=Kq2x2mg
x=q2 L2πε0mg13

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About this question

This is a previous-year question from JEE Main 2021, covering the Oscillations 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.