How much is the Rutherford estimated the dimension of nucleus ?

If the total binding energies of ${ }_1^2 H ,{ }_2^4 He ,{ }_{26}^{56} Fe$ and ${ }_{92}^{235} U$ nucleiare $2.22,28.3,492$ and $1786 MeV$ respectively, identify the most stable nucleus of the following.

From the statements given below:$(A)$ The angular momentum of an electron in $n^{\text {th }}$ orbit is an integral multiple of $h$.$(B)$ Nuclear forces do not obey inverse square law.$(C)$ Nuclear forces are spin dependent.$(D)$ Nuclear forces are central and charge independent.$(E)$ Stability of nucleus is inversely proportional to the value of packing fraction.

Choose the correct answer from the options given below :

Antiparticle of electron is

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 other is a neutron. In such a case

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