The deuteron is bound by nuclear forces just as $H-$ atom is made up of $p$ and $e$ bound by electrostatic forces. If we consider the force between neutron and proton in deuteron as given 1 e 2 in the form of a Coulomb potential but with an effective charge $e' \,:\,F = \frac{1}{{4\pi { \in _0}}}\frac{{e{'^2}}}{r}$ . estimate the value of $(e'/e)$ given that the binding energy of a deuteron is $2.2\, MeV.$

The decay of a proton to neutron is :

Write the unit of mass and its definition.

Obtain approximately the ratio of the nuclear radii of the gold isotope $^{197}_{79} Au$ and the silver isotope $^{107}_{47} Ag$ .

Write the value of $R_0$ constant.