Question

If the total binding energies of ${ }_{1} H ^{2},{ }_{2} He ^{4}, 26 Fe ^{56}$ and $_{92} U ^{235}$ nuclei are $2.22,28.3,492$ and $1768 MeV$ respectively, then identify the most stable nucleus out of the following.

• A. ${ }_{26} F e ^{56}$
• B. ${ }_{1} H ^{2}$
• C. ${ }_{92} U ^{235}$
• D. ${ }_{2} He ^{4}$

Answer 1

Answer: (A)

Binding energy/nucleon,
${ }_{1} H ^{2}: 2.22 / 2=1.11 MeV$
${ }_{1} He ^{4}: \frac{28.3}{4}=7.07 MeV$
${ }_{26} Fe ^{56}: \frac{492}{56}=8.78 MeV$
${ }_{92} U ^{235}: \frac{1786}{235}=7.6 MeV$
Binding energy/nucleon is maximum for $_{26} Fe ^{56}$, hence it is most stable element.