We can roughly estimate the electron velocity of a bound electron using the Bohr model. Therefore we can state that the bound electron velocity in a hydrogen 1s orbital results in an electron whose velocity is a large enough fraction of the speed of light to assign it a relativistic mass. The unbound electron's, (moving at zero velocity), relativistic mass is less than the bound electron's relativistic mass. The difference in the two when plugged into Einstein's mass equivalency equation will therefore allow us to determine the amount of energy a bound electron yields upon ionization and being brought to a dead stop. If the braking radiation is in excess of the ionization radiation then each bound electron becomes a potential energy source.
@sparks in other words in the photoelectric effect if the ejected electrons yield more energy than the impinging photons?mmm