Two spheres of equal masses, one of which is a thin spherical shell and the other a solid, have the same moment of inertia about their respective diameters. The ratio of their radii will be
a)		b)		c)		d)

(c)

Let the radii of the thin spherical and the solid sphere are  and  respectively.

Then the moment of inertia of the spherical shell about their diameter

                                                           …(i)

and the moment of inertia of the solid sphere is given by

                                                             …(ii)

Given that the masses and moment of inertia for both the bodies are equal, then from Eqs. (i) and (ii)