Questions tagged [electromagnetism]
The classical theory of electric and magnetic fields, both in the static and dynamic case. It also covers general questions about magnets, electric attraction/repulsion, etc. Distinct from electrical-engineering.
19,213
questions
0
votes
2
answers
34
views
Maxwell Stress Tensor on a Capacitor Plate Given a Dielectric
Given a capacitor with large plates (area $A$) separated by a dielectric with relative permittivity $\varepsilon_r$ and thickness $g$, I believe the Maxwell stress tensor states that the force on each ...
2
votes
1
answer
269
views
How to derive magnetic moment for integrated circuit level?
Imagine we have a circuit on the xy-plane, with a random geometry (it just need to be closed). I want to calculate the magnetic moment of this setup:
$$\vec{m} = \frac{1}{2} \int_V d^3 x' \vec{x}' \...
0
votes
0
answers
28
views
About the notation for TEM waves
I just came across this article where the term "$\mathrm{TE}_{101}$ microwave mode" is mentioned. Other than the basics of TEM waves which I learned in Griffiths, this is the first time I ...
0
votes
0
answers
30
views
Seeking Advanced Study Guidance in Electromagnetism [closed]
I hope this post doesn't break any community rules, I've tried to look for such but couldn't find.
I am concluding my first undergraduate course in Electromagnetism next week. I am confident in my ...
4
votes
1
answer
808
views
What's the coordinate of the Landau tube?
The Hamiltonian of a three-dimensional electron gas in a static magnetic field $\vec{B}$ is :
$$\hat{H}=\frac{(\hat{\vec{p}}+e\hat{\vec{A}})^2}{2m}$$
If choosing $\vec{B}=B\vec{e_z}$ and using Landau ...
0
votes
1
answer
260
views
How is the index notation for the electromagnetic potentials defined?
I don't understand, how the $\vec{A}$ potential is defined in the covariant formulation of the Maxwell-Equations.
I am using the metric $(+,-,-,-)$.
The electric field (SI-Units) is defined as:
$$
\...
0
votes
1
answer
552
views
Lenz law - Direction of induced current
I understand the Lenz Law is such that it tells us that the induced current must be in a direction that makes the end of the solenoid facing the magnet behave as a North Pole to repel the magnet’s ...
0
votes
1
answer
58
views
How do I find the wavelength of an EM wave derived from an accelerating electron, given its acceleration?
I understand the Larmors formula, but I can't find any material regarding wavelength of a single photon.
1
vote
2
answers
160
views
How to solve Relativistic Lorentz Force equation if $\gamma$ is not constant?
I am trying to numerically obtain the trajectory of an electron inside a periodic magnetic field $\mathbf{B}$, taking into account that the relativistic factor $\gamma$ is not a constant (the electron ...
0
votes
1
answer
257
views
Motor Effect Experiment
I recently saw an demonstration (image below) where the motor effect was being shown. They used the fact that forces come in pairs (Newton's third law) and so when current goes through the copper rod, ...
0
votes
0
answers
36
views
A question on perturbed flux function
Given a magnetic field $\mathbf{B}=B_{0}\left(\dfrac{xz}{z_{s}^{2}},\dfrac{yz}{z_{s}^{2}}, 1-2\left( \dfrac{x^{2}}{r_{s}^{2}}+\dfrac{y^{2}}{r_{s}^{2}}\right) -\dfrac{z^{2}}{z_{s}^{2}}\right)$ with the ...
0
votes
0
answers
18
views
What is radial and axial component of magnetic induction of a coil? [closed]
I am sorry if my question is stupid, but can someone explain what are the radial and axial component of magnetic induction of a coil. I am reading an article about the magnetic field generated by coil....
2
votes
1
answer
289
views
Materials to complement "Interacting Electrons and Quantum Magnetism" by Assa Auerbach
Does anyone know of any material, such as lecture notes from a university, that can complement the sometimes brief chapters of the book "Interacting Electrons and Quantum Magnetism" by Assa Auerbach?
...
0
votes
1
answer
259
views
How does changing the angular frequency ω of the generator affect the current flowing in the circuit and the power transferred to the electric motor?
When an electric motor is used with an electric generator, the situation can be viewed as an RLC circuit where the generator is an AC power source. The source produces a sinusoidal AC voltage with an ...
2
votes
1
answer
414
views
Eddy current brake with superconductor
There are eddy current brakes used with metal plates to stop trains. It converts kinetic energy of the metal plate to heat via eddy current on it. So what if we have a superconducting metal plate and ...