On Aug 13, 2007, at 3:32 PM, Harry Veeder wrote:
Horace,
You seem to feel you must rely exclusively on measures of voltage and
amperage to determine the absolute charge.
These are the common instruments at hand, and I think they are good
enough, though they aren't even necessary to accomplish an electron
fugacity experimental design.
However, you could direct a beam
of electrons near the spheres and look for a deflection in the
beam. If the
deflection is towards the sphere it is positively charged. If the
deflection
is away from the sphere it is negatively charged. Along with a
measure of
voltage this would be enough to determine the absolute charge...or
not?
Harry
This is where I was headed and why I chose spheres instead of
plates. When well between two plates the answer to the above is no,
because it is only the relative potentials of the plates that
determine the electron motion. Same goes for the line exactly
between the two sphere centers. But, as you point out, this is not
true if you get well away from that center line (and you are well out
in space where there is no field from the universe.) Then the
absolute net charge on the plates is clearly visible by which way the
electron goes, which can be away from the spheres or towards them.
Horace Heffner
http://www.mtaonline.net/~hheffner/
