Question

If mass of $U^{235}=235.12142amu$, mass of $U^{236}=236.1205$ amu and mass of neutron $=1.008665amu$, 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 $U^{235}=235.121420amu$
Mass of one neutron $=1.008665amu$
Sum of the masses of $U^{235}$ and neutron $=236.130085$
$=236.130amu$
Mass of one atom of $U^{236}=236.123050amu=236.123amu$
Increase in mass when one neutron is removed from
$U^{236}=236.136-236.123=0.007amu$
$\therefore$ Energy required to remove one neutron
$=0.007\times 931MeV$
$=6.517MeV=6.5MeV$