Question

Raw and boiled eggs are made to spin on a smooth table by applying the same torque. The egg that spins faster is : (assume egg to be symmetrical and remains as it is even after boiling)

• A. Raw egg
• B. Boiled egg
• C. Both will have same spin rate
• D. Difficult to predict

Answer 1

The correct option is B Boiled egg

moment of inertia of the boiled egg is less than that of raw egg because the mass of the boiled egg is concentrated near the axis of rotation whereas in raw egg the mass will get concentrated at the surface away from the axis of the rotation.
$I_B<I_r$
$c=I\alpha$
$c$ is constant.
$\therefore I\alpha$ is constant.
$\therefore I\propto \frac{1}{\alpha }$
$\therefore {\alpha }_B>{\alpha }_r(\because I_B<I_R)$
$\therefore$ The boiled egg will spin faster.