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 $2.2\, MeV.$

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Write the definition of $Z, A$ and $N$ by stating the structure of a atom.

Assume that protons and neutrons have equal masses. Mass of a nucleon is $1.6 \times 10^{-27}\,kg$ and radius of nucleus is $1.5 \times 10^{-15} A ^{1 / 3}\,m$. The approximate ratio of the nuclear density and water density is $n \times 10^{13}$. The value of $n$ is $……………..$

The graph between $log\, R$ and $log\, A$ where $R$ is the nuclear radius and $A$ is the mass number is