AIPMT PRELIMS2005Physics-Rotational Motion

AIPMT PRELIMS 2005 Physics Angular Momentum MCQ Question

Type: MCQ-conceptual-Medium-Class 11

Two bodies have their moments of inertia I and 2I respectively about their axis of rotation. If their kinetic energies of rotation are equal, their angular momenta will be in the ratio:

A

1 : 4

B

√2 : 1

C

4 : 1

D

1 : √2

Correct Answer

Option D

Detailed Explanation

The kinetic energy of rotation is given by KE = (1/2)Iω². For equal KE, I₁ω₁² = I₂ω₂². Since I₂ = 2I₁, ω₂ = ω₁/√2. Angular momentum L = Iω, so L₁/L₂ = I₁ω₁/I₂ω₂ = 1/√2.

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