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

Two nucleons are at a separation of $1 \times 10^{-15} \ m$. The net force between them is $F_1$ if both are neutrons,$F_2$ if both are protons,and $F_3$ if one is a proton and the other is a neutron. In such a case:

$\pi$ mesons can be

If the radius of $_{13}^{27}Al$ is $3.6 \ fm$,then the radius of the $_{52}^{125}Te$ nucleus will be ........ $fm$.

Write the formula for the average radius of a nucleus.

The ratio of the volume of an $Al^{27}$ nucleus to its surface area is (Given,$R_0 = 1.2 \times 10^{-15} \ m$):