Q88 / 180 · AIIMS 2019 (25 May) · Physics
A thin wire of mass $M$ and length $L$ is bent to form a circular ring. The moment of inertia of this ring about its axis is
- A$\frac{1}{4} M L^2$
- B$\frac{1}{\pi^2} M L^2$
- Correct answerC$\frac{1}{4 \pi^2} M L^2$
- D$\frac{1}{12} M L^2$
Solution
A wire of length $L$ is bent to form a circular ring of radius $R$,
$\therefore \quad 2 \pi R=L$ or $R=\frac{L}{2 \pi}$
Moment of inertia of the circular ring about its axis is
$I=M R^2=\frac{1}{4 \pi^2} M L^2$
Hence, the correct answer is option: 'C'.