Q. The energy liberated on complete fission of $1\ kg$ of $\ _{92}U^{235}$ is (Assume $200\ MeV$ energy is liberated on fission of 1 nucleus)
A) $8.2 \times 10^{10}J$
B) $8.2 \times 10^{9}J$
C) $8.2 \times 10^{13}J$
D) $8.2 \times 10^{16}J$
Explanation
(c) Mass of a uranium nucleus
$= 92 \times 1.6725 \times 10^{- 27} + 143 \times 1.6747 \times 10^{- 27}$
$= 393.35 \times 10^{- 27}kg$
Number of nuclei in the given mass
$= \frac{1}{393.35 \times 10^{- 27}} = 2.542 \times 10^{24}$
Energy released $= 200 \times 2.542 \times 10^{24}MeV$
$= 5.08 \times 10^{26}MeV = 8.135 \times 10^{13}J = 8.2 \times 10^{13}J$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.