Question

In a nuclear reactor the number of $U^{235}$ nuclei undergoing fissions per second is $4\times {10}^{20}$. If the energy released per fission is $250MeV$, the total energy released in 10 hours is
( $1eV=1.6\times {10}^{-19}J$)

• A. $576\times {10}^{6}J$
• B. $576\times {10}^{12}J$
• C. $576\times {10}^{15}J$
• D. $576\times {10}^{18}J$

Answer 1

The correct option is B $576\times {10}^{12}J$

Energy released per fission = $250MeV=250\times {10}^6\times 1.6\times {10}^{-19}J$

Number of fissions per second = $4\times {10}^{20}$

Thus number of fissions in 10 hours = $4\times {10}^{20}\times 10\times 3600$

Thus total energy released in 10 hours =$4\times {10}^{20}\times 10\times 3600\times 250\times {10}^6\times 1.6\times {10}^{-19}J$

$\approx 576\times {10}^{12}J$