The moment of inertia of a thin rod about an axis passing through its mid point and perpendicular to the rod is 2400 g cm^2. The length of the 400 g rod is nearly :

1. 72.0 cm

2. 8.5 cm

3. 17.5 cm

4. 20.7 cm

Doubtly Asked 30 Oct 2026 NEET UG 2024 Practice test neet Save WhatsApp Report

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Answer: 2. 8.5 cm

Key idea: For a thin rod about its midpoint and perpendicular to its length, \(I=\frac{ML^2}{12}\).

\(L^2=\frac{12I}{M}=\frac{12\times2400}{400}=72\), so \(L=\sqrt{72}\approx8.5\) cm.

Option 2.

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

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