Question

In nuclear forces between two protons, between two neutrons and between a proton and a neutron are $ f_{pp} $ . $ F_{nn} $ and $ f_{pn} $ respectively, then :

• A. $ f_{pn} < f_{pp} < f_{nn} $
• B. $ f_{pp} = f_{nn} = f_{pn} $
• C. $ f_{pp} < f_{pn} < f_{nn} $
• D. $ f_{pp} > f_{pn} > f_{nn} $

Answer 1

Answer: (B)

The nucleon-nucleon force is the same irrespective of whether the nucleons are protons or neutrons once the Coulomb repulsion has been taken into account. Thus, the nuclear force is charge symmetric or charge independent. For example the determination of nuclear sizes from the study of mirror nuclei is based on this charge independence of the nuclear force.
Hence, $f_{pp}=f_{nn}=f_{p n}$