Question

Number of Uranium$-235$ nuclei required to undergo fission to give $9\times 10$${}^{13}$ joule of energy is

• A. $2.8125\times 10$${}^{24}$
• B. $28.125\times 10$${}^{24}$
• C. $281.25\times 10$${}^{24}$
• D. $28215\times 10$${}^{24}$

Answer 1

The correct option is A $2.8125\times 10$${}^{24}$

No of nuclei $=n$,

Energy for fission of an atom of U $=200MeV$

$9\times {10}^{13}J=n\times 200\times 1.6\times {10}^{-13}J$

$n=2.8125\times {10}^{24}$