Question

The mass defect in a particular nuclear reaction is 0.3 grams. The amount of energy liberated in kilowatt hours is. (Velocity of light = $3 \times 10^{8}m ⥂ / ⥂ s$)

• A. $1.5 \times 10^{6}$
• B. $2.5 \times 10^{6}$
• C. $3 \times 10^{6}$
• D. $7.5 \times 10^{6}$

Answer 1

Answer: (D)

$7.5 \times 10^{6}$

Answer 2

$E = \Delta m.c^{2}$ $\Rightarrow E = \frac{0.3}{1000} \times (3 \times 10^{8})^{2} = 2.7 \times 10^{13}J$

$= \frac{2.7 \times 10^{13}}{3.6 \times 10^{6}} = 7.5 \times 10^{6}kWh$.