For a historical and empirical view look up Faraday Cage or Faraday's Pail.
Let the conductor be isolated. The net charge on the surface is neutral. Now bring in a source that generates an E field external to the conductor. The free charge in the conductor moves about in a tiny tiny tiny...
I'm not an authority on superconductors, however, I am confident that the scientific community reserves the term "super" for very special cases of conductors, fluids, states of matter, etc. I agree the All About Circuits reference should use the term "perfect conductor" in its description, and...
My recollection is about 0.9c for a DC signal (infinite frequency) in a copper conductor, but I don't recall doing an analysis myself.
This reference treats the transmission line as a superconductor for analysis, and yields results similar to the concept expressed by xantox (note k is the...
I regard a field as a mathematical model to predict changes in momentum (force) over distance specified with or without a time delay. These momentum interactions can be of course microscopic or macroscopic and through such interactions we infer the existence of a field and build a model...
The simple case of the charge changing velocity (accelerating) without colliding with anything is then that of an electron (or proton) moving in a constant circle in a magnetic field at constant velocity vC.
It seems to me the conservation of momentum and Newton's Third Law would hold upon...
My understanding is that in the modern view Conservation of Momentum can be used to derive Newton's Third Law for an isolated system. Momentum p = mv is conserved, then the terms F = dp/dt in a time-derivative of conserved momentum should include action reaction pairs.
I haven't studied the...
Comment on my philosophy. Galileo, who is recognized as a pioneer of empirical methods, said the (untested) ideas of the philosophers gave him a great pain! Now this flies in the face of conventional "wisdom," which regards emotion as playing no part in theoretical science! I have discovered it...
I use the "paint" program in the Windows accessories folder under the Start menu. The tools are sufficient for making a quick rough sketch with some practice. Use black and white and Save As *.png or *.gif seems to produce a small file size for resource economy.
The capacitance of a system...
The OP asks about the similarities between General Relativity and Electromagnetic waves, so I'm posting this link, which has a number of (apparently informed) papers near the bottom on Gravity and Relativity:
http://www.metaresearch.org/home.asp [Broken]
I've always wondered how space...
Sketch attached of my understanding of the question. Choice of ground node is arbitrary. There is an E-field in the gap between the plates which may or may not be a linear function from 0 to 100V.
As long as a 100V source is connected across the electrodes, the difference in potential is 100V.
The definition of potential is the work W required to move a positive test charge q+ from one equipotential surface to another. Where q+ = e is the elemental charge.
V2 - V1 = dW/q+
You...
Interference patterns exist in EM fields. The classic example of particle-wave duality is light (or electrons) passing through a double-slit.
http://en.wikipedia.org/wiki/Double-slit_experiment
I'm not sure how this applies to gravity or electrostatic field models. I'll think about your...
My understanding is that the electrostatic field lines must terminate on a region of static charge. This is similar to gravity terminatining on a region with mass, although I am not familiar with the theory of gravity waves (time delay in the influence of gravitational force).
The motion of...
My old college physics textbook illustrates the experiment as a cork ball, with positive charge, lowered on a silk thread into a conducting can, with the can sitting atop an isolator stand.
Before the cork ball touches the bottom or any part of the can, the inside can surface takes a negative...
This quote is from the Wiki article link cited by Bob S above.
In p-n junctions (diodes, transistors, photodetectors) the charge carriers, which are holes and electrons, are generated via some random process that introduces shot noise.
In a good conductor there are always many free...
In a good conductor (such as copper) there are many free electrons in the conduction band. The discrete energy levels of each electron in a single atom merge into one continuous band of energy in the crystal lattice structure of many atoms, so a band with no discrete energy levels occurs.
The...
According to your wiki link, shot noise only applies when there are a relatively small number of electrons in the flow of current, so that noise becomes a statistically significant factor in the average flow, but this factor diminishes in significance as the magnitude of current flow increases...
The general question says, Shouldn't a DC current emit EM waves? The simple answer is yes, a static B field is generated by a DC current per Ampere's Law. There is a coupling of the electric current and magnetic field whenever charge flows.
If the specific question of detecting each electron...
Bob S,
Typically I would sketch the problem in paint and post if it really needs attention.
I found a problem in my Field & Waves book which says a static E field can be shaped by a dielectric lens. I am not sure if a charged parabolic surface provides a focus point for a static E field...
Please note my analysis showing q = 0 in the figure at post #16 is incorrect. The charge in the dielectric at a plate surface is always smaller than the opposite charge on the metal plate.
Please refer to these two references and/or a good physics/electrostatics textbook for proper analysis...
There is a simpler model that applies as well to smooth DC flow, Ampere's Law.
As the question implies, a DC current in a wire induces a static B field around the wire.
The wiki doesn't do a great job explaining it, but here's the link...
I spoke too soon. Let two capacitors have the same capacitance C and maximum voltage rating V. In each configuration let the terminal voltage be Vt.
Series Configuration:
Equivalent capacitance: Cs = C/2.
Terminal voltage: Vt = 2V.
Substutute into (1/2)*Cs*(Vt)^2 = (1/2)*(C/2)*(2V)^2...
Scroll down on this reference and see the equivalent capacitance Ceq:
http://www.physics.sjsu.edu/becker/physics51/capacitors.htm
In theory both configurations could be used to store the same energy. In practice, if the caps are voltage rated for maximum voltage, then stacking two in...
LiteHacker,
I had an excellent fields and waves professor 20 years back. Now I need to refresh most of the knowledge ...
You need to look also at the properties of a conductor, and how a surface charge is induced while it remains an equipotential surface.
There may be a free charge flow...
Excellent reference on basic electrostatic field problems and parallel plate capacitor:
http://www.ac.wwu.edu/~vawter/PhysicsNet/Topics/ElectricForce/FlatSheet.html [Broken]
http://www.ac.wwu.edu/~vawter/PhysicsNet/Topics/Capacitors/ParallCap.html [Broken]
Bob S. & others:
Excellent reference on basic electrostatic field problems and parallel plate capacitor:
http://www.ac.wwu.edu/~vawter/PhysicsNet/Topics/ElectricForce/FlatSheet.html [Broken]
http://www.ac.wwu.edu/~vawter/PhysicsNet/Topics/Capacitors/ParallCap.html [Broken]
If the permitivity (dielectric constant) is that of free space, I believe the boundary conditions and integral above would give the constant field of a parallel plate capacitor after applying superposition of the two E fields upon the space between the plates. Of course in a practical capacitor...
Field and Wave Electromagenetics by David K. Cheng (1985).
Boundary Conditions at Conductor / Free Space Interface
E = \frac{\rho_{s}}{\epsilon_{0}}
"The normal component of the E field at a conductor-free space boundary is equal to the surface charge density (rho) on the conductor...