Re: Since k varies but not G suggests an Eather

"Randy Poe" <poespam-trap@xxxxxxxxx> wrote in message
news:1150390321.411340.191770@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

FrediFizzx wrote:
"Randy Poe" <poespam-trap@xxxxxxxxx> wrote in message
news:1150315966.145594.15400@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

The k is the same as k_e in your expression. Your expression is for
the
"vacuum". Not generalized for other media.

Medium equations are merely rewritings of the vacuum equations
(which are always valid). Maxwell's vacuum equations can equally
well be applied in a medium, but it is just more convenient to
consider D and H than E and B.

Similarly, it is always valid, ALWAYS, that the total electrostatic
force felt by a charge q is the sum of k*Q*q/r^2 over all other
charges Q, including those which make up the medium, where
k is the VACUUM value. Whatever equation you are looking at
was derived from this. It isn't a separate equation, just one
which is more convenient for charges embedded in dielectrics.

If your test charge q is in the linear, isotropic and uniform dielectric
medium with the other charges, then it is silly to use the "vacuum"
value of k. Use the dielectric eps. ;-)

div E = rho/eps in SI units where eps is the electric permittivity of
the medium.

It actually become much
more clear in SI units. See Jackson 3rd edition.

That's still not a reference.

How about a chapter name or number, a section name or number
that I can correlate to my 2nd ed so we can discuss the same
equations in Jackson?

You won't find it in the 2nd ed at all since it is not in SI units. It
is on page 154 in the 3rd ed. Section is 4.3 "Elementary Treatment of
Electrostatics with Ponderable Media". But I am curious as to how he
treats it in cgs.

And you can also look at Griffith's "Intro. to Electrodynamics" 3rd ed.
starting on page 178 thru 185.

Meanwhile, perhaps you want to review the derivation of the
equation you're looking at.

Like I was saying, it is much more clear to deal with this in SI units.
The force between two charges in the above describe medium in SI units
will be,

F = q1*q2/(4pi*eps*r^2) (that is eps and not eps0)

FrediFizzx

Quantum Vacuum Charge papers;
http://www.vacuum-physics.com/QVC/quantum_vacuum_charge.pdf
or postscript
http://www.vacuum-physics.com/QVC/quantum_vacuum_charge.ps
http://www.arxiv.org/abs/physics/0601110
http://www.vacuum-physics.com

.

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