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99 Percentile Qs Bank for JEE MainPhysicsRotational Motion

From a uniform wire, two circular loops are made (i) P of radius r and (ii) Q of radius n r . If the moment of inertia of Q about an axis passing through its centre and perpendicular to its plane is 8 times that of P about a similar axis, the value of n is (diameter of the wire is very much smaller than i or n r )

Options

  1. A8 2
  2. B6 2
  3. C4 2
  4. D2 2

Correct answer

D. 2 2

Step-by-step solution

Moment of inertia of circular loop, I=m r^2 Given, aligned I_Q & =8 I_D m r_Q^3 & =8 m_p r_D^2 aligned aligned m_p (n r_p )^2 & =8 m_p r_p^2 n^2 & =8 n=2 2 aligned

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