Re: conserving charges ? /Faraday

[Bob Sciamanda <trebor@VELOCITY.NET>]

Ludwik wrote:
> Consider a “another source” near the disectable capacitor, perhaps the
> column of a Van de Graaff machine. What is the worse possible scenario?
> The free charges( +Q1 and -Q2 on the opposite aluminum blocks of our
> setup) are no longer equal in magnitude. So what? We are not interested
> in free charges on metallic plates. We always get rid of them by
discharging
> the setup before the removal of dielectric sheets. The observed net
charges
> are presumably bound to sheets.

In your worst case scenario: Shorting the capacitor plates while in the E
field of a Van de Graff would polarize the shorted capacitor.

> how can "the proximity of other conductors (grounded or not) could
> complicate the situation"?  How can other sources contribute to the
> net bound charges appearing ielectric plates?
> Ludwik Kowalski

I have no idea how charges get trapped onto the dielectric plates (other
than triboelectric effects), but I think it would be well to be assured
that charges induced on/by nearby objects/fields  (or connections to
earth ground) do not disturb the symmetry of your two - plate capacitor.

Bob Sciamanda
Physics, Edinboro Univ of PA (ret)
trebor@velocity.net
http://www.velocity.net/~trebor