Question

A nucleus with mass number $240$ breaks into two fragments, each of mass number $120$. The binding energy per nucleon of unfragmented nuclei is $7.6\text{MeV}$ while that of fragments is $8.5\text{MeV}.$ Energy released in the process is

• A. $216\text{MeV}$
• B. $0.9\text{MeV}$
• C. $9.4\text{MeV}$
• D. $804\text{MeV}$

Answer 1

The correct option is A $216\text{MeV}$

Mass number of reactant $=240$

BE per nucleon $=7.6\text{MeV}$

Mass number of products $=120$

BE per nucleon of product $=8.5\text{MeV}$

$\text{Total gain in BE = (BE) of products - (BE) of reactants.}$

$=[120+120]\times 8.5-[240\times 7.6]]$

$=\left(240\right)\times 8.5-240\times 7.6$

$=(240\times 0.9)=216\text{MeV}$

Hence, $\left(A\right)$ is the correct answer.