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

If the ratio of the mass numbers of two nuclei is $27 : 125$, then the ratio of their surface areas is

Nuclei with magic numbers of protons $Z = 2, 8, 20, 28, 50, 82$ and magic numbers of neutrons $N = 2, 8, 20, 28, 50, 82, 126$ are found to be very stable.
$(i)$ Verify this by calculating the proton separation energy $S_p$ for $^{120}Sn$ $(Z = 50)$ and $^{121}Sb$ $(Z = 51)$. The proton separation energy for a nuclide is the minimum energy required to separate the least tightly bound proton from a nucleus of that nuclide. It is given by $S_p = (M_{Z-1, N} + M_H - M_{Z, N})c^2$. Given:
$^{119}In = 118.9058 \ u, ^{120}Sn = 119.902199 \ u, ^{121}Sb = 120.903824 \ u, ^1H = 1.0078252 \ u$
$(ii)$ What does the existence of magic numbers indicate?

$A$ nucleus has mass number $A_1$ and volume $V_1$. Another nucleus has mass number $A_2$ and volume $V_2$. If the relation between mass numbers is $A_2 = 4 A_1$,then $\frac{V_2}{V_1} = $ . . . . . . .

What is the ratio of the radii of the nuclei $_{13}^{27}Al$ and $_{52}^{125}Te$?

The force between a proton and a proton in a nucleus is .......