Assume that a neutron breaks into a proton and an electron. The energy released during this process is: (mass of neutron =1.6725×10−27kg, mass of proton =1.6725×10−27kg, mass of electron =9×10−31kg).

[a] 10n→11H+−1e0+v¯+Q The mass defect during the process Δm=mn−mH−me=1.6725×10−27             −(1.6725×10−27+9×10−31kg) =−9×10−31kg The energy released during the process E=Δmc2 E=9×10−31×9×1016=81×10−15 Joules E=81×10−151.6×10−19=0.511MeV