1) If the nuclear fission, piece of uranium of mass 5.0 g is lost, the energy obtained in kWh is? A) $1.25 \times 10^{7}$ B) $2.25 \times 10^{7}$ C) $3.25 \times 10^{7}$ D) $0.25 \times 10^{7}$ Answer: Option AExplanation: As we know, energy $E= \triangle mc^{2}$ $=0.5 \times 10^{-3} \times (3 \times 10^{8})^{2}$ $=4.5 \times 10^{13}J$ $=\frac{ 4.5 \times 10^{13}}{3.6 \times 10^{6}}=1.25 \times 10^{7} kWh$
