Q. Binding energy per nucleon verses 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) $Y \rightarrow 2Z$
B) $W \rightarrow X + Z$
C) $W \rightarrow 2Y$
D) $X \rightarrow Y + Z$
Explanation
(c) Energy is released in a process when total binding energy (B.E.) of the nucleus is increased or we can say when total $B.E.$ of products is more than the reactants. By calculation we can see that only in case of option $(c)$, this happens
Given $W \rightarrow 2Y$
$B.E.$ of reactants $= 120 \times 7.5 = 900\ MeV$
and $B.E.$ of products $= 2 \times (60 \times 8.5) = 1020\ MeV$
$i.e.,B.E.$ of products > $B.E.$ of reactants
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.