two disk have same mass and thickness.their material are of densities p1 & p2.the ratio of moment o inertia is-

Let the mass of both discs be M. Let radius of one disk be R₁ and that of the other be R₂. Let their thickness be h.

 

The disc is of cylindrical shape. So, its volume is

 

Now, the moment of inertia of disc of mass M and radius R along the axis perpendicular to disc at centre is

 

The density of disc is

 

Thus, the ratio of moment of inertia is: