## Question

In a nuclear reaction the mass defect is 2.0 x 10^{-6} g. Calculate the energy released, given that the velocity of light is 3.0 x 10^{8} m/s.

### Answer

Mass Defect, m = 2.0 x 10^{-6} g = 2.0 x 10^{-9} kg

Velocity of light, c = 3.0 x 10^{8} m/s

Energy released, E = mc^{2}

E = mc^{2} = 2.0 x 10^{-9} x (3.0 x 10^{8})^{2} = 2.0 x 10^{-9} x 9.0 x 10^{16} = 1.8 x 10^{8} Joules