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Two rings of radius R and nR made of same material have the ratio of moment of inertia about an axis passing through centre is 1: 8 . The value of n is

Options

  1. A2
  2. B2 2
  3. C4
  4. D1 / 2

Correct answer

A. 2

Step-by-step solution

Ratio of moment of inertia of the rings I ₁ I ₂ = ( M ₁ M ₂ ) ( R ₁ R ₂ )² aligned =& ( l₁ l₂ ) ( R₁ R₂ )²= ( 2 R 2 n R ) ( R n R )² &( = linear density of wire = constant ) I ₁ I ₂ = 1 n ³ = 1 8 (given) n ³=8 n =2 aligned

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