Translations:Adventist Youth Honors Answer Book/Health and Science/Physics/115/en
From Pathfinder Wiki
A gamma ray with an energy of 1.022MEV (Million Electron Volts) can spontaneously form an electron anti-electron (Positron) pair. Each particle has mass that has the equivalent energy of .511MEV and one has a positive charge and one a negative charge. Because one is negatively charged and one is positively charged, they are likely to be attracted to each other and recombine and form a gamma ray again. The gamma ray has no charge or mass.
