Under an influence of a field, the electron distribution can be - Theory A - http://img147.imageshack.us/img147/1690/quantumelectrondistribu.png [Broken] or Theory B - [PLAIN]http://img115.imageshack.us/img115/1690/quantumelectrondistribu.png [Broken] Theory B can be state wrong cause cause if this was so, the charge density made would have been extremely high. But using the same principle (that at one place here are tons of electrons, while at the other there are none) we can also model a lower charge density...when only a few positive ions will be exposed, i.e at the place where the electrons reside, the density of electrons will not be that high as compared to the natural charge density of the metal. For example - In this case, using the same principle (theory B), the charge gained is low - [PLAIN]http://img115.imageshack.us/img115/1690/quantumelectrondistribu.png [Broken] While with this is high - http://img152.imageshack.us/img152/1690/quantumelectrondistribu.png [Broken] It might also be stated by someone that the cause the minimum number of electrons that can be withdrawn from a positive ion in a metal (considering the temperature is feasible) is equal to the number of its valence electrons, there should be a minimum amount charge that the metal will gain if charged, and higher charges will be a multiple of this minimum charge, which does not happen practically - Minimum amount of charge - http://img164.imageshack.us/img164/1690/quantumelectrondistribu.png [Broken] Other charges will be a multiple of this - http://img4.imageshack.us/img4/1690/quantumelectrondistribu.png [Broken] i.e we have twice the charge now. However, this is not true considering this can also happen - http://img246.imageshack.us/img246/1690/quantumelectrondistribu.png [Broken] Or the valence electrons have been just displaced by a bit, resulting in partial polarisation. So theory B is explaining all possible scenarios, with no glitches........at least that's what it appears. The problem that arises from theory A is that -- how can some electrons not move (when the field falls), while the others start moving...the field doesn't know how to discriminate among electrons, its gonna influence all of the electrons, so all the electrons will move together, leaving a few places in the metal completely electron-less...while at other places, even electron density. So by the above point, theory B is showing a weak sign............so which one is correct?