Re: Since k varies but not G suggests an Eather


Sue... wrote:
guskz@xxxxxxxxxxx wrote:
Sue... wrote:

snip static

<< Thus, Maxwell's equations for the propagation of
electromagnetic waves through a dielectric medium
are the same as Maxwell's equations for the propagation
of waves through a vacuum (see Sect. 4.7), except that ,
where n = sqrt eps >>
http://farside.ph.utexas.edu/teaching/em/lectures/node98.html

Sue...

OK then how do you explain the following information retrieved from the
web:

permittivity = electric field strength / dielectric displacement

snip static


Correct static: E= kQq/r^2 and which is that of a capacitor and the
permittivity ("k") varies with the medium amd therefore affects the
force of charges. Static in the term that the charges are not allowed
to get closer but each charge is moving like crazy on it's own side of
the border (plate). In Maxwell's F= k_space Qq/r^2 the paired charges
are not nescessarily moving linearly in space but can remain orbiting
within a certain region of space (HENCE STATIC)



<<The equation given below is derived from Coulomb's law
and is subject to the limitations of Coulomb's law i.e. it
applies ONLY FOR Q BEING AN ISOLATED POINT CHARGE. >>
http://www.plus2physics.com/electrostatics/study_material.asp?chapter=2

Try to focus on that box of homogenous dielectric that Poe and
Fitzpatrick have Maxwell looking good in, or I am going to ask
the god of Faraday rotation to reposess the liquid crystals in
your wrist watch. :o)

It is 'Catch 22' learning where eps and mu appear to be
defined with circular logic. In a sense they are. But
Fitzpatrick has the parameters of the space well defined
so you don't fly off on a semantic tangent or a different
unit systems. It is a good 'practice area' where you
can learn to fly charges around. If you get lost, the
vector math is just a two clicks away.

IOW...'Fitz' has removed, as much as possible, the
magnetic effects that complicate the issue.
http://farside.ph.utexas.edu/teaching/em/lectures/node98.html


When you are comfortable with the space, you can change
the pressure, move it near a conductor or a ferrite bead
or magnetise its atoms so your watch display works again.

Sue...












- Randy

.

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