Q 11-06-021NEETJEE MainEAMCET 2012 (Engineering)Easy
Two solid spheres A and B, each of radius $R$, are made of materials of densities $\rho_A$ and $\rho_B$ respectively. Their moments of inertia about a diameter are $I_A$ and $I_B$ respectively. The value of $\dfrac{I_A}{I_B}$ is
Answer: (C) $\dfrac{\rho_A}{\rho_B}$
Same radius, so $I = \dfrac{2}{5}mR^2 \propto m \propto \rho$:
$$\frac{I_A}{I_B} = \frac{\rho_A}{\rho_B}$$
Solution by Sreeraj P, M.Sc Physics