When a $U^{238}$ nucleus,initially at rest,decays by emitting an alpha particle with speed $u$,what will be the recoil velocity of the residual nucleus?

Two spherical nuclei have mass numbers $216$ and $64$ with their radii $R_1$ and $R_2$ respectively. The ratio,$\frac{R_1}{R_2}$ is equal to

Who discovered the neutron?

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 breaks into two nuclear parts,which have their velocity ratio $2:1$. The ratio of their nuclear radii will be

Find the ratio of the radii of the nuclei $_{13}Al^{27}$ and $_{52}Te^{125}$.