Question

Binding energy per nucleon vs mass number curve for nuclei is shown in the figure. W, X, Y and Z are four nuclei indicated on the curve. The process that would release energy is

• A. $Y\to 2Z$
• B. $W\to X+Z$
• C. $W\to 2Y$
• D. $X\to Y+Z$

Answer 1

The correct option is C $W\to 2Y$

Energy is released in a process when total binding energy of the nucleus (= binding energy per nucleon $\times$ number of nucleon) is increased or we can say, when total binding energy of products is more than the reactants. By calculation we can see that only in case of option (c) this happens.
Given $W\to 2Y$
Binding energy of reactants = $120\times 7.5=900MeV$
and binding energy of products = $2(60\times 8.5)=1020MeV>900MeV$