On the bombardment of a neutron with Boron,an $\alpha$-particle is emitted. The product nucleus formed is:

The electric potential at the surface of an atomic nucleus $(Z = 50)$ of radius $9.0 \times 10^{-15} \, m$ is

The maximum potential energy due to electrostatic repulsion between two hydrogen nuclei is nearly (radius of the nucleus $= 1.1 \ Fermi$). $\left[ \frac{1}{4 \pi \epsilon_0} = 9 \times 10^9 \ N \ m^2 \ C^{-2} \right]$ (in $MeV$)

$A$ 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

Define nuclear force.

The radius of the nucleus of an atom whose mass number is $125$ is: