JEE Main 2019PhysicsRotational MotionMediumMCQ

JEE Main 2019 — Rotational Motion Question with Solution

JEE Main 2019 (12 Jan Shift 1)

Question

Let the moment of inertia of a hollow cylinder of length 30 cm (inner radius 10 cm and outer radius 20 cm ), about its axis be I . The radius of a thin cylinder of the same mass such that its moment of inertia about its axis is also I, is:

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Show full solutionCorrect option: A
Correct answer
A16 cm

Step-by-step explanation

Moment of inertia of a hollow cylinder whose inner radius id r and outer radius is R is given as 

I=m(R2+r2)2

m202+1022=mk2

K=400+1002; K=250

K=510 cm

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About this question

This is a previous-year question from JEE Main 2019, covering the Rotational Motion 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.