Question

If mass of $U ^{235}=235.12142\, amu$, mass of $U ^{236}=236.1205$ amu and mass of neutron $=1.008665\, amu$, then the energy required to remove one neutron from the nucleus $U^{236}$ is nearly about

• A. 75 MeV
• B. 6.5 MeV
• C. 1 eV
• D. zero

Answer 1

Answer: (B)

Mass of one atom of $U ^{235}=235.121420\, amu$
Mass of one neutron $=1.008665\, amu$
Sum of the masses of $U ^{235}$ and neutron $=236.130085$
$=236.130\, amu$
Mass of one atom of $U ^{236}=236.123050\, amu =236.123\, amu$
Increase in mass when one neutron is removed from
$U ^{236}=236.136-236.123=0.007\, amu$
$\therefore$ Energy required to remove one neutron
$=0.007 \times 931\, MeV$
$=6.517\, MeV =6.5\, MeV$