If the mass number of an atom is $A = 40$ and its electron configuration is $1{s^2},\;2{s^2},\;2{p^6},\;3{s^2},\;3{p^6}$, the number of neutrons and protons in its nucleus will be

If $r_1$ and $r_2$ are the radii of the atomic nuclei of mass number $64$ and $125$ respectively, then the ratio $(r_1/r_2)$ is

Specify the mass of proton in kilogram and in the $'u'$ unit. 

A heavy nucleus at rest breaks into two fragments which fly off with velocities in the ratio $8 : 1$. The ratio of radii of the fragments is

Given the mass of iron nucleus as $55.85\,u$ and $A=56$, find the nuclear density?

The deuteron is bound by nuclear forces just as $H-$ atom is made up of $p$ and $e$ bound by electrostatic forces. If we consider the force between neutron and proton in deuteron as given 1 e 2 in the form of a Coulomb potential but with an effective charge $e' \,:\,F = \frac{1}{{4\pi { \in _0}}}\frac{{e{'^2}}}{r}$ . estimate the value of $(e'/e)$ given that the binding energy of a deuteron is $2.2\, MeV.$