The strongest force in nature is

The ratio of the density of oxygen nucleus $(_{8}^{16}O)$ and helium nucleus $(_{2}^{4}He)$ is (in $: 1$)

If the mass number of an atom is $A = 40$ and its electron configuration is $1s^2, 2s^2, 2p^6, 3s^2, 3p^6$,the number of neutrons and protons in its nucleus will be

Two nuclei of $Cu^{64}$ are in contact with their surfaces touching. What is the electrostatic potential energy between them in $MeV$?

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

The nuclear radius of a hydrogen atom is approximately . . . . . . . (in $fm$)