When an electron-positron pair annihilates, the energy released is about

Electron and positron are identical in all respect except that charges on them are opposite when an electron and a positron meet together, they completely annihilate to each other and two photons are produced. e++e-→2γThe rest mass energy of each particle, electron and positron is 0.511 MeV. Hence, 2 x 0.511 MeV energy of photon is converted to rest mass energy of two particles. Total energy isE'=2 x 0.511 x 106 x 1.6 x 10-19 E'=1.6 x 10-13J