The ratio of masses and radii of two circular rings are $1 : 2$ and $2 : 1$ respectively. What is the ratio of their moments of inertia about their central axes?

In the diagram shown below,all three rods are of equal length $L$ and equal mass $M$. The system is rotated such that rod $B$ is the axis. What is the moment of inertia of the system?

$A$ cylinder of mass $500 \ g$ and radius $10 \ cm$ has a moment of inertia about an axis passing through its centre and parallel to its length equal to:

Assertion $(A)$: The moment of inertia of a steel sphere is larger than the moment of inertia of a wooden sphere of the same radius.
Reason $(R)$: Moment of inertia is independent of the mass of the body.
The correct one is:

$A$ circular disc of radius $b$ has a hole of radius $a$ at its centre (see figure). If the mass per unit area of the disc varies as $\sigma(r) = \frac{\sigma_0}{r}$,then the radius of gyration of the disc about its axis passing through the centre is

The moment of inertia of a solid cylinder of mass $20 \ kg$,length $1 \ m$,and radius $0.2 \ m$ about its geometric axis is (in $kg \cdot m^2$):