In a photoelectric experiment a student uses a light source whose frequency is greater than that needed to eject electrons from
a certain metal. However, after continuously shining the light on the same area of the metal for a long period of time the student notices that the maximum kinetic energy of ejected electrons begins to decrease, even though the frequency of the light is held constant. How would you account for this behavior?
Based on the scenario being described it seems that this is due to the later ionization energies, namely the 2nd, 3rd etc... seem to be much higher than the first. Therefore this causes an excess amount of energy to be used in order to remove the electrons, thus causing less energy to be left after the process is over. This would be the best explanation for this behavior.
