The ratio of the radius of gyration of a circular disc to that of a circular ring,each of the same mass and radius,about their respective central axes is:

The adjoining figure shows a disc of mass $M$ and radius $R$ lying in the $X-Y$ plane with its centre on the $X$-axis at a distance $a$ from the origin. Then the moment of inertia of the disc about the $X$-axis is

$A$ flywheel is constructed such that its entire mass is concentrated at the rim because:

The radius of gyration of a uniform thin rod of length $L$ about an axis passing normally through its centre of mass is:

The radius of gyration of a circular disc of radius $R$ and mass $m$ rotating about its diameter as an axis is:

From a uniform wire, two circular loops are made: $(i)$ $P$ of radius $r$ and (ii) $Q$ of radius $nr$. If the moment of inertia of $Q$ about an axis passing through its centre and perpendicular to its plane is $8$ times that of $P$ about a similar axis, the value of $n$ is (diameter of the wire is very much smaller than $r$ or $nr$). (in $\sqrt{2}$)