Why is there a lot of energy released during a nuclear reaction?

Answer 1

In a nuclear reaction, mass is converted to its equivalent in energy. The energy released is described by the relativistic equation E = mc2. 'E' is energy released, 'm' is mass in kilograms, and 'c' is the speed of light; this is around 3 x 108 (metres per second, but units are unimportant). Squaring this gives us an even larger number - to most people anyway - of around 9 x 1016. Thus for even a small mass like one nanogram, one-billionth of a gram, being converted to energy, there is a release of almost 9 x 10 joules.