Question

For nuclei with mass number close to $119$ and $238$, the binding energies per nucleon are approximately $7.6 \,MeV$ and $8.6 \,MeV$ respectively. If a nucleus of mass number $238$ breaks into two nuclei of nearly equal masses, what will be the approximate amount of energy released in the process of fission?

• A. 214 MeV
• B. 119 MeV
• C. 2047 MeV
• D. 1142 MeV

Answer 1

Answer: (A)

$119 \rightarrow 7.6\, MeV$
$238 \rightarrow 8.6 \,MeV$
$238 \rightarrow 119+119$
$E_{i}=238 \times 8.6, $
$E_{f}=238 \times 7.6$
$\therefore E_{f}-E_{i}=-238 \,MeV$
A negative value indicates the fission cannot take place.
The data given are incorrect.
The BE per nucleon values are swapped in question, it should have been $7.6 \,MeV$ for $238$ and $8.6\, MeV$ for $119$.
Thus $\Delta E =+238 \,MeV$.
Thus $214$ is closest and will be taken as right answer