Natural Science Forum / Physics / Electromagnetism / July 2005

Eric R. Dietz, the author of a remarkable article "Force on a
dielectric slab: Fringing field approach" (American Journal of Physics,
72 1499), considers that the force dF = (P\nabla)EdV acts on a volume
element dV of the material of a dielectric slab partially inserted

The noise power from a conductor is
Power = k T B
were k is Boltzmann's constant
T absolute temperature

Hi everybody!! Being brief, i understand how works magnetostrictive
effect, but i don't know what causes it, Do you know!? please tell
me!! thanks!!

http://abcnews.go.com/Technology/wireStory?id=939695
ARLINGTON, Va. Jul 14, 2005 - For years, the U.S. military has
explored a new kind of firepower that is instantaneous, precise and
virtually inexhaustible: beams of electromagnetic energy.

I'm aware that when a magnetised steel ship passes over an electrical
conductor (cable) lying on the sea floor, a induced current is produced in
the cable. This is the basis of the navy's "indicator loop" antisubmarine
detection technology form WW1 and WW2. A current is induced ...

Gotta a metal detector which is beeping for no reason when people pass
by with their walkie-talkies as close as even 5 meters. The
walkie-talkies use 450Mhz frequency, so I know I have to block the
radio wave interferences:

I'm trying to solve an electrodynamics problem in spherical coordinates and
need to use Legendre Polynomials.  Can anyone tell me what is the correct
mathematical value for LegendreP[-1,1] supposed to be?  Is it +1 or -1, and
more importatnly WHY? I have a math book here which ...

A colleague of mine described how one of his university professors
managed to float a garbage can lid in mid-air.  My colleague remembers
very little from the demostration, except that it was in
electromagnetics class, that the professor needed to spin the lid, and

Via email I was asked about proton decay. I do not have time to discuss
science via email.
The Atom Totality theory would say that all the forces of physics are
Coulomb force. They all boil down to becoming a Coulomb force. That

For a current in a tube (like the shield of coaxial cable), it is said
that there is no magnetic field from this current inside the tube.  The
only field is external to the tube.  Why is this?  What properties are
necessary for this to be true?

2            Compton effect is a Doppler effect
Ed 05.07.19  ----------------------------------
Abstract
--------

please pardon my ignorance in that topic.
I wanted to know if charging (negatively) a given metal
plate, like in a capacitor, would reduce the work function
of that plate, or not.

I need this very specific information. I'd like to know
the difference in electron vibration (no matter how
miniscule) when sine waves AC and square waves Alternating
Current are inputted into the wire.

Ampere's Law states that the net mmf around a closed loop equals the
current enclosed.  This is often used to demonstrate how there is no H
field in the doughnut hole of a toroid, for example.  But consider a
pair of wires carrying equal and opposite current.  Any closed loop

Can anyone explain me how to calculate the current between two objects
which has a high voltage field between them?
Let's say you have an object with area A cm^2 located L cm from an
object with inf. size (ground), and there is a voltage of V volt