Question

How can matter be converted into energy?

Answer 1

Matter can be converted into energy by annihilation, fission, and fusion.

These are mentioned in

http://socratic.org/questions/how-are-matter-and-energy-related

Some examples are

Annihilation occurs when an electron and a positron meet. They annihilate each other and produce two γ ray photons, each with an energy of 511 keV.

`e^-` + `e^+` → γ + γ

Fission is a process in which a nucleus splits into two smaller nuclei. For example,

`""_92^235"U" + _0^1"n" → _56^141"Ba" + _36^92"Kr" +3_0^1"n"` + energy

Fusion is a process in which two nuclei join to form a larger nucleus. For example,

`""_1^2"H" + _1^3"H" → _2^4"He" + _0^1"n"` + energy

Hope this helps.