The energy released by the fission of \( 500\ \mathrm{g} \) of \( {}^{235}\mathrm{U} \) in a fission reaction is
(Given: energy released per fission of \( {}^{235}\mathrm{U} = 200\ \mathrm{MeV} \))
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → \( 2.56\times10^{26}\ \mathrm{MeV} \)
Find the number of nuclei in 500 g from the molar mass and Avogadro’s number, then multiply by the energy per fission.
\( \displaystyle N = \frac{500\,\mathrm{g}}{235\,\mathrm{g\,mol^{-1}}}\times6.022\times10^{23}\,\mathrm{mol^{-1}} = 1.281\times10^{24} \)
\( E = N\times200\,\mathrm{MeV} = 1.281\times10^{24}\times200\,\mathrm{MeV} \)
\( E \approx 2.56\times10^{26}\,\mathrm{MeV} \)