The radius of gyration of a disc of mass $50\,g$ and radius $2.5\,cm$,about an axis passing through its centre of gravity and perpendicular to the plane,is ....... $cm$.

The atomic numbers of elements $X, Y$ and $Z$ are $19, 21$ and $25$ respectively. The number of electrons present in the $M$-shell of these elements follow the order:

In biennial plants,normally the number of carpels is:

The angle between the lines whose direction cosines satisfy the equations $l+m+n=0$ and $l^2+m^2-n^2=0$ is

If a line in space makes angles $\alpha, \beta,$ and $\gamma$ with the coordinate axes, then the value of $\cos 2\alpha + \cos 2\beta + \cos 2\gamma + \sin^2 \alpha + \sin^2 \beta + \sin^2 \gamma$ is equal to:

Genus represents