Q 11-10-011JEE MainEAMCET 2012 (Engineering)Easy
When the temperature of a body increases from $t$ to $t + \Delta t$, its moment of inertia increases from $I$ to $I + \Delta I$. The coefficient of linear expansion of the body is $\alpha$. The ratio $\dfrac{\Delta I}{I}$ is
Answer: (D) $2\alpha\Delta t$
$I \propto$ (mass)(length)$^2$, and the mass does not change. Every length grows by the factor $(1 + \alpha\Delta t)$:
$$\frac{\Delta I}{I} \approx 2\alpha\Delta t$$
Solution by Sreeraj P, M.Sc Physics