Question

The energy released during the fission of 1 kg of uranium :

• A. $9\times {10}^{20}ergs$
• B. $9.0\times {10}^{10}ergs$
• C. $9.0\times {10}^{18}ergs$
• D. $9.0\times {10}^{8}ergs$

Answer 1

The correct option is A $9\times {10}^{20}ergs$

Fission of uranium will be

${}_{92}^{235}U{+}_0^{1}n{⟶}_{56}^{141}Ba{+}_{36}^{92}Kr+3_0^{1}n$

Average energy released in the above reaction for 1 atom is $215$ MeV.

No. of moles taken is, $\frac{m}{M}=\frac{1\times 1000}{235}=4.2553mol$.

For 1 atom, energy released is $215\times {10}^6\times 1.6\times {10}^{-19}=344\times {10}^{-13}J$.

$1mol=6.023\times {10}^{23}atoms$

For $435.53$ mol,total energy released will be

$4.2553\times 6.023\times {10}^{23}\times {344\times 10}^{-13}=8.81\times {10}^{13}J=8.81\times {10}^{20}erg$.