JEE Main 2026 Physics question
A solid sphere of mass M and radius R is divided into two unequal parts. The smaller part having mass M/8 is converted into a sphere of radius r and the larger part is converted into a circular disc of thickness t and radius 2R. If I₁ is moment of inertia of a sphere having radius r about an axis through its centre and I₂ is the moment of inertia of a disc about its diameter, the ratio of their moment of inertia I₂/I₁ = .
Answer: (B)
Solution
Same density: (M/8) ∝ r³ and M ∝ R³ give r = R/2. I₁ = (2/5)(M/8)(R/2)² = MR²/80. I₂
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