Question

When ${}_{92}{U}^{235}$ undergoes fission, 0.1% of its original mass is changed into energy. $9\times {10}^{x}J$ of energy is released if $1kg$ of ${}_{92}{U}^{235}$ undergoes fission, then the value of $x$ is ___

• A. 92
• B. 23
• C. 13
• D. 33

Answer 1

The correct option is C 13

Given,

Mass defect = $0.1$% of $1kg$

By using $E=\Delta m.c^2$, where $E$ = Energy, $\Delta m$ = Mass defect and $c$ = Speed of light

$\Rightarrow E=(\frac{0.1}{100}\times 1)(3\times {10}^8{)}^2=9\times {10}^{13}J$.