All Questions
Tagged with electromagnetism homework-and-exercises
1,551
questions
29
votes
6
answers
9k
views
Can a gym be built to supply electricity to homes? [closed]
A moving magnet induces a current in a conductor, then shouldn't we be able to generate electricity through manual labour?
I was thinking about building a gym that used magnets as weights. People ...
- 1,323
26
votes
3
answers
9k
views
Deriving the speed of the propagation of a change in the Electromagnetic Field from Maxwell's Equations
I've been told that, from Maxwell's equations, one can find that the propagation of change in the Electromagnetic Field travels at a speed $\frac{1}{\sqrt{\mu_0 \epsilon_0}}$ (the values of which can ...
- 5,990
21
votes
4
answers
41k
views
Derivation of self-inductance of a long wire
Currently I am stuck, trying to derive the self-inductance of a long wire. According to literature it should be
$$L=\frac{\mu_r\mu_0l}{8\pi}$$
and in literature its derived by looking at the energy ...
- 1,573
20
votes
3
answers
2k
views
Electromagnetism problem: where does the magnetic field come from?
Consider the following problem:
Consider a plane with uniform charge density $\sigma$. Above the said plane, there is a system of conducting wires made up of an U-shaped circuit on which a linear ...
- 571
18
votes
2
answers
22k
views
Is magnetic force non-conservative? [duplicate]
If magnetic field is conservative, then why not the magnetic force?
My professor thinks it is non conservative but he couldn't explain to me why?
- 181
15
votes
4
answers
57k
views
Transverse Magnetic (TM) and Transverse Electric (TE) modes
I'm reading and working my way through "Plasmonics Fundamentals" by Stefan Maier and I've come across a step in the workings that I'm struggling to understand when working out the electromagnetic ...
- 962
14
votes
4
answers
5k
views
Why are EM plane waves transverse?
I was reading Griffiths' Introduction to Electrodynamics, specifically Section 9.2.2 on plane waves. I can see that if we want a transverse wave traveling in the $z$ direction that we are only going ...
- 561
13
votes
9
answers
57k
views
What's the core difference between the electric and magnetic forces?
I require only a simple answer. One sentence is enough... (It's for high school physics)
- 245
13
votes
2
answers
5k
views
Deriving Biot-Savart Law from Maxwell's Equations
As an exercise, I've been trying to derive the Biot-Savart law from the second set of Maxwell's equations for steady-state current
$$\begin{align}&\nabla\cdot\mathbf{B}=0&&\nabla\times\...
- 838
13
votes
1
answer
560
views
How can I find the position of an image charge when the boundary is parabolic or hyperbolic?
If the position of some charge $Q$ is known, the boundary condition is $u=0$ on some parabolic surface, and we know the image charge has its electric volume of $Q'$, then how can I determine the ...
- 147
12
votes
2
answers
7k
views
Proving Gauge invariance of Schrodinger Equation
I am trying to proof explicitly that Schrodinger equation:
$$ i\hbar \partial_t \psi = \left[ -\frac{1}{2m}\left(\frac{\hbar}{i}\nabla-q\vec{A}\right)^2+qV \right]\psi$$
remains the same under the ...
- 980
12
votes
1
answer
3k
views
Lorentz force derivation in quantum mechanics [closed]
In Sakurai and Napolitano, chapter 2, there's a derivation of the QM Lorentz force.
Given $$H=\frac{1}{2m}\left(\mathbf{p}-\frac{e\mathbf{A}}{c}\right)^2+e\phi = \frac{\mathbf{\Pi}^2}{2m}+e\phi$$
...
- 877
12
votes
1
answer
453
views
Is the uniqueness theorem correct in superconductivity?
There is an uniqueness theorem in electromagnetism. It says that the solution of Maxwell's Equations is determined uniquely by boundary conditions.
We can treat superconductivity as a completely ...
- 1,181
11
votes
3
answers
2k
views
Propagator of Maxwell-Chern-Simons theory
I need to compute the "topologically massive photon" propagator.
I've started with:
$$
\mathcal{L}=-\frac{1}{4}F_{\mu\nu}F^{\mu\nu} + \frac{\mu}{4}\epsilon^{\mu\nu\lambda}A_\mu\partial_\nu ...
- 929
11
votes
1
answer
2k
views
Chern-Simons Energy-Momentum Tensor
I'm assuming the following statement is true. I'm not finding any reference which shows that explicitly.
Statement: Chern-Simons term is a topological one and does not contribute to the Energy-...
- 944