1. 1 : √(2) 2. 2 : 1 3. √(2) : 1 4. 4 : 1

Answer: 3. √(2) : 1 Radius of gyration is k=√(I/M) . For a disc, about the normal axis through the centre I=1/2MR² ; about a diameter I=1/4MR² . k₁/k₂=√(1/2/1/4)=sqrt2:1 Option (3) is correct.

Topic: Moment of inertia, radius of gyration, MI of simple objects· Rotational Motion

The ratio of the radius of gyration of a thin uniform disc about an axis passing through its centre and normal to its plane to the radius of gyration of the disc about its diameter is :

1. 1 : \(\sqrt{2}\)

2. 2 : 1

3. \(\sqrt{2}\) : 1

4. 4 : 1

Doubtly Asked 30 Oct 2026 NEET UG 2022 Practice test neet Save WhatsApp Report

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Answer: 3. \(\sqrt{2}\) : 1

Radius of gyration is \(k=\sqrt{I/M}\).

For a disc, about the normal axis through the centre \(I=\tfrac12MR^2\); about a diameter \(I=\tfrac14MR^2\).

\(\dfrac{k_1}{k_2}=\sqrt{\dfrac{1/2}{1/4}}=\sqrt2:1\)

Option (3) is correct.

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

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The ratio of the radius of gyration of a thin uniform disc about an axis passing through its centre and normal to its plane to the radius of gyration of the disc about its diameter is :

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