Question

The moment of inertia of two spheres of equal masses about their diameters is the same. One is hallow, then the ratio of their diameters is

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

Moment of inertia of solid sphere = Moment of inertia of hollow sphere.

$\Rightarrow \frac{2}{5}M{R}_{1^2}=\frac{2}{3}M{R}_{2^2}$

$\Rightarrow \frac{R_1}{R_2}=\sqrt{\frac{5}{3}}\Rightarrow \frac{D_1}{D_2}=\sqrt{\frac{5}{3}}$