ExamBro
ExamBro
MHT CET · Physics · Rotational Motion

Two circular loops \(\mathrm{P}\) and \(\mathrm{Q}\) of radii \(r\) and \(n r\) respectively are made from a uniform wire. Moment of inertia of \(Q\) about its axis is four times that of \(\mathrm{P}\) about its axis. The value of \(n\) is

  1. A \((2)^{\frac{2}{3}}\)
  2. B \((2)^{\frac{1}{3}}\)
  3. C \(2\)
  4. D \(\sqrt{2}\)
Verified Solution

Answer & Solution

Correct Answer

(A) \((2)^{\frac{2}{3}}\)

Step-by-step Solution

Detailed explanation

Given, \(I_Q=4 I_P\).
Let \(m\) be the mass per unit length of wire.
\(\therefore m \times 2 \pi n r(n r)^2=4\left[(m 2 \pi r) r^2\right]\)
Implies \(n^3=4\)
\(\Rightarrow n=4^{1 / 3}\)