An explosion of atomic bomb releases an energy of `7.6xx10^(13)J`. If 200 MeV energy is released of fission of one `.^(235)U` atom calculate (i) the number of uranium atoms undergoing fission, (ii) the mass of uranium used in the bomb.

Explanation

Energy released `(E )=7.6xx10^(13)J`
Energy released on fissions (E )= 200 MeV
`= 200xx10^(6)xx1.6xx10^(-19)J`
(i) No. of fissions `(n)=(E')/(E )`
`=(7.6xx10^(13))/(200xx10^(6)xx1.6xx10^(-19))`
`therefore n=2.375xx10^(24)` atoms
But Avogadro number
`N=6.023xx10^(23)` atoms
Mass of uranium `(m)=(n xx235)/(N)`
`= (2.375xx10^(24))/(6.023xx10^(23))`
`= 926.66 g`