$A$ nucleus has mass number $\alpha$ and radius $R_{\alpha}$. Another nucleus has mass number $\beta$ and radius $R_{\beta}$. If $\beta = 8\alpha$, then $R_{\alpha}/R_{\beta}$ is:

The atomic masses of two isotopes of an element are $34.98 \ u$ and $36.98 \ u$ and their relative abundances are $75.4 \%$ and $24.6 \%$ respectively. The average atomic mass of the element is: (in $u$)

Two nuclei of $Cu^{64}$ are in contact with their surfaces touching. What is the electrostatic potential energy between them in $MeV$?

Which of the following is most unstable?

$A$ nucleus with atomic mass number $A$ produces another nucleus by losing $2$ alpha particles. The volume of the new nucleus is $60$ times that of the alpha particle. The atomic mass number $A$ of the original nucleus is:

Pick out the correct statement from the following.