The strongest force among the following forces in nature is

Which physical quantity is measured in barn?

The radius $R$ of a nucleus of mass number $A$ can be estimated by the formula $R = (1.3 \times 10^{-15}) A^{1/3} \; m$. It follows that the mass density of a nucleus is of the order of $(M_{\text{prot}} \cong M_{\text{neut}} = 1.67 \times 10^{-27} \; kg)$.

The nuclear force between two nucleons is explained by

Define nuclear force.

Which graph in the following diagrams correctly represents the potential energy $U$ of a pair of nucleons as a function of their separation $r$?