The Bohr radius tells us of 2 Rydberg photons involved in pair production when 13.6eV stress is imposed upon an H-atom. The Gamma factor is solved. Mass decrease does happen. Binding energy is easily understood as the energy of one Rydberg photon. In this example electron-positron pairs are described and arrived at from experimental data. However, pair production can occur for any other set of photon pairs, an electron being just one tiny example. We must not restrict our association of charge with just an electron.