Assume that protons and neutrons have equal masses. Mass of a nucleon is $1.6 \times 10^{-27}\,kg$ and radius of nucleus is $1.5 \times 10^{-15} A ^{1 / 3}\,m$. The approximate ratio of the nuclear density and water density is $n \times 10^{13}$. The value of $n$ is $.................$

What kind of a force does neutron-neutron ?

The force acting between proton and proton inside the nucleus is

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 :

Briefly explain the discovery of neutrons and how can it be demonstrated ?

Mark the correct statement