On Aug 13, 2007, at 2:59 AM, Michel Jullian wrote:
Measuring relative surface potentials between two
electrodes simply doesn't tell you if there are excess surface
electrons on one or both or neither. It still seems pretty obvious
to me.
You can say that three times it won't make it true, whatever Lewis
Carroll says ;-)
Come on, what you describe is a capacitor, there are excess
electrons on the surface of the most negative electrode facing the
most positive one, of a very predictable total charge given by:
C*Delta_V = C*(potential of most positive electrode - potential of
most negative electrode)
Elementary EE stuff. Only potential differences matter I tell you!
Suppose a 1 m radius metal sphere, sphere A, has 1 coul more negative
charges than positive. Suppose a 1 m radius metal sphere, sphere B,
has 2 coul more negative charges than positive. They have a finite
potential difference V at some separation D. The same is true for
two spheres X and Y where X has 2 coul less negative charges than
positive, and Y has 1 coul less negative charges than positive.
Sphere, charge in coul:
A -1
B -2
X +2
Y +1
There is no difference in relative potentials, but the two differ
significantly in electron fugacity, the significant variable.
Horace Heffner
http://www.mtaonline.net/~hheffner/
