How Does Grounding Affect the Electric Field of a Charged Plate?

[Hootenanny]

I don't know why, actually.. it struck me after I had posted. It's only if we place the grounded metal-stick on the side with the deficit of negative charges that additional negative charges are drawn from ground, since the atoms are fixed in the lattice.

Correct! For example, one can charge a conducting sphere using this method. If one places a conducting sphere with a grounding cable in an external electric field then the electrons will move to one side of the sphere and down the grounding cable (provided that the grounding cable is on the correct side) such that the area immediately around the grounding cable is electrically neutral. However, the side opposite the grounding cable with have a net positive charge. Now if the grounding cable is detached and the external electric field removed, then the sphere will have a deficit of electrons and hence will have gained a net positive charge.

 

[pzlded]

Drawing an electron from a grounded metal-stick is current. Current must obey Kirchoff's law (point charges in = point charges out).

Does ground really supply an electron to the plate? A capacitor has the same energy w/ or w/o a grounded plate. Is there an energy advantage to drawing an electron from ground?