Diagram of electron–positron annihilation, producing 2(511 keV) photons leaving in opposite directions.How to find the photon energy ? Use Einstein s mass energy relation as 2 equal mass electron/positron produce 2 photons means one electron produce one photon. E= mass of electron x speed of light square. Two photons are produced as conservation of momentum is necessary.
If reverse can occur , what photon energy can produce a electron-positron pair?
