Assertion (A) : Force in case of nucleons is different to that in case of electrons and protons.

Reason (R) : Binding Energy in case of nucleons is very large compared to that in case of atoms.

(A) and (R) are both true and (R) is the correct explanation of (A).

In case of electron and proton, the electrostatic force comes into play and the resulting binding energy is of the order of eV. But in case of nucleons, the force of much greater magnitude is required because it has to overcome the electrostatic repulsion in protons and also it has to bind the electrically neutral neutrons. Hence, the resulting force in case of nucleons is much greater, of the order of MeV.