Question

An explosion of atomic bomb releases $7.6\times {10}^{13}J$ energy. If $200MeV$ energy is released on fission of one ${}^{235}U$ atom, then the number of uranium atoms undergoing fission and the mass of uranium used in the tom bomb

• A. $1.756\times {10}^{24};976.66gm$
• B. $1.756\times {10}^{24};956.66gm$
• C. $2.375\times {10}^{24};936.66gm$
• D. $2.375\times {10}^{24};926.66gm$

Answer 1

The correct option is D $2.375\times {10}^{24};926.66gm$

$1MeV$ $=1.6\times {10}^{-13}J$
No. of atoms used $=\frac{7.6\times {10}^{13}}{200\times 1.6\times {10}^{-13}}$

$=2.375\times {10}^{24}$
Mass of $U=\frac{2.375\times {10}^{24}}{6.022\times {10}^{23}}\times 235$

$=926.6gm$