In each fusion reaction, 411H nucleus are used. Energy released per Nuclei of 11H=426.7MeV ∴ Energy released by 2 kg hydrogen (EH) =12000×NA×426.7MeV & ∴ Energy released by 2 kg Vranium (EV)=2352000×NA×200MeV So, EVEH=235×4×20026.7=7.84 ∴ Approximately close to 7.62