A solid and a hollow sphere of the same mass have the same outer radius. Which one has a larger radius of gyration?

Explanation

The mass of the solid sphere is distributed uniformly from its centre. On the other hand the mass of the hollow sphere is distributed over a comparatively further distance. More the distance of the mass distribution from the axis of ratation of two bodies of identical mass having the same outer radius more the radius of gyration. In this sense, mass of the hollow sphere is distributed over a comparatively larger distance from the axis of rotation than that of the solid sphere and hence the radius of gyration of the hollow sphere will be greater.