The radius of germanium $(Ge)$ nuclide is measured to be twice the radius of ${ }_4^9 Be$. The number of nucleons in $Ge$ will be

$A$ nucleus at rest splits into two nuclear parts having the same density and radii in the ratio $1:2$. Their velocities are in the ratio $\qquad$ . (in $:1$)

An atom of mass number $15$ and atomic number $7$ captures an $\alpha$-particle and then emits a proton. The mass number and atomic number of the resulting product will respectively be

Which of the following is true for a sample of isotopes containing $^{235}U$ and $^{238}U$?

If the nuclear forces between two protons,two neutrons,and a proton-neutron are denoted by $F_{pp}$,$F_{nn}$,and $F_{pn}$ respectively,then:

${ }_{92}^{238} U$ and ${ }_{90}^{236} Th$ are $\qquad$ of each other.