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

The correct option is D $7.5\times {10}^6$

$E=\Delta m.c^2\Rightarrow E=\frac{0.3}{1000}\times (3\times {10}^8{)}^2=2.7\times {10}^{13}J$
$=\frac{2.7\times {10}^{13}}{3.6\times {10}^6}=7.5\times {10}^{6}kWh$.