If $M$ is the atomic mass and $A$ is the mass number,the packing fraction is given by

The nucleus having the highest binding energy per nucleon is

The figure shows a plot of binding energy per nucleon $E_b$ against the nuclear mass $M$. $A, B, C, D, E, F$ correspond to different nuclei. Consider four reactions:
$(i) \, A + B \to C + \varepsilon$
$(ii) \, C \to A + B + \varepsilon$
$(iii) \, D + E \to F + \varepsilon$
$(iv) \, F \to D + E + \varepsilon$
where $\varepsilon$ is the energy released. In which reactions is $\varepsilon$ positive?

Derive the formula for the binding energy of a nucleus by explaining the mass defect of the nucleus and write the formula for the binding energy per nucleon.

$1 \text{ a.m.u.}$ is equivalent to

The binding energy of a nucleus is a measure of its