What is the relationship between AC electricity and transverse waves in copper?

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Discussion Overview

The discussion explores the relationship between alternating current (AC) electricity and transverse waves in copper as a medium. Participants examine the wave-like behavior of AC current and its implications in the context of electromagnetic theory, including the mathematical representation of waves and the properties of electric and magnetic fields.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant suggests interpreting AC current as a transverse wave in copper, proposing a wave equation and discussing the role of the medium in wave propagation.
  • Another participant presents the complete wave equation for electromagnetic waves, introducing concepts of permittivity, permeability, and conductivity, and discusses the relationship between electric and magnetic fields in the context of power transmission along wires.
  • Some participants express interest in the idea that all physical phenomena could be understood through wave behavior, questioning whether structural dysfunction could be analyzed through the sound waves produced.
  • There is a clarification regarding the distinction between the magnetic field (H) and magnetic induction (B), with references to their definitions and relationships in materials.
  • One participant challenges the definitions of B and H, emphasizing the dependence of magnetic induction on the material being magnetized.

Areas of Agreement / Disagreement

Participants generally agree on the wave-like interpretation of AC electricity, but there are competing views regarding the definitions and roles of the magnetic fields H and B, as well as the implications of wave behavior in understanding physical phenomena.

Contextual Notes

The discussion includes unresolved definitions and relationships between electric and magnetic fields, as well as assumptions about the nature of waves in different media. The mathematical representations presented are not fully resolved, and the implications of these concepts remain open to interpretation.

HWGXX7
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I was wondering if I may interprete AC current as a tranverse wave trough copper as medium. So this wave behaviour has a general wave-form written as: [tex]\zeta(x,t)=\zeta_{0}sin(kx-\omega.t)[/tex]
This is a solution to the partial differential equation:
[tex]\frac{\partial^{2}\zeta}{\partial t^{2}}=K.\frac{\partial^{2}\zeta}{\partial x^{2}}[/tex]

K is the medium-depent factor, which will determine the wave velocity.
Because the electric!ty will only be a one direction flow (assume we talk about a period in 50Hz current), the derivative to x direction wille be meaningless..I think.

But electricity is the flow of electrons, so the medium itself will be responsible for the wave. This bothers my whole perception of the above approach...

Anyway who shares same ideas?

grtz
 
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The complete wave equation for any electromagnetic wave component φ is
[tex]\frac{\partial^2\psi}{\partial t^2 }=\frac{1}{\varepsilon \mu} \frac{\partial^2 \psi}{\partial x^2}- \frac{\sigma}{\varepsilon}\frac{\partial \psi}{\partial t }[/tex]
where ε and μ are the permittivity and permeability, and σ is the conductivity of the medium. In free space, the speed of light is c = 1/√ (εμ).

The general solution of the above wave equation is of the form
[tex]\psi \left( x,t \right)=\psi_o e^{-ax}e^{i \left( \omega t - bx \right)}[/tex]
where the e-ax factor represents attenuation and ei(ωt-bx) represents propagation.

If power (electromagnetic wave) is traveling along two parallel wires, the power may be represented by two orthogonal fields (E and H) traveling between the wires (look up Poynting vector), and there are no E fields in the wires, unless the wires have resistance. A longitudinal current I in the wire is orthogonal to the magnetic field H between the wires.

Bob S
 
Thank for the reply, so in general the approach to see electricty (AC) as a wave through material is correct.

The use of H instead of B is because H is the magnetic field and B is just magnetic induction, correct?

In extend, I also assume the whole world is than build up from only (a)periodic waves.

I find it very interesting that maybay it is possible to determine all behaviour from just wave behaviour, instead of analysing structures.

Could it be possible for example to analyse the disfunction of a structure just by de sound wave it produces?

Sorry if I go beyond my question, just wondering.

grtz
 
HWGXX7 said:
Thank for the reply, so in general the approach to see electricty (AC) as a wave through material is correct.

The use of H instead of B is because H is the magnetic field and B is just magnetic induction, correct?

[itex]\mathbf{H}\ \equiv \ \frac{\mathbf{B}}{\mu_0}-\mathbf{M}[/itex] (from Wikipedia)

and thus
[itex]B = \mu_0(H + M)[/itex]

The B field is thought of as sum of the magnetic field due to the magnetization of the material (M) and the H field.
 
Last edited:
Well, but B isn't the field itself? The gradient of amps.winding is H. This has the characteristic of a field. B is magnetic induction and equals permeability.H

H is the concept of magnetic field, but de induction B which occurs, depents on which material is being magnetised.
 

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