All Questions
Tagged with electromagnetism homework-and-exercises
258
questions with no upvoted or accepted answers
2
votes
1
answer
58
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Manipulation of the diffusive term in MHD induction equation
I am trying to solve the magnetohydrodynamic (MHD) equations with a spatially varying resistivity, $\eta$. To remove some of the numerical stiffness from my finite volume approach, I am trying to get ...
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2
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0
answers
154
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Debye length for a debye shield
I understand debye length and even the concept of debye shielding, but quantitatively I'm a little confused. If the debye shield has a potential of $$\Phi=\frac{q}{4\pi\epsilon_{0}r}\exp\left({\frac{-...
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2
votes
1
answer
51
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Questions on Forces involved in oscillating mass dipole
Say we have two balls of radius $R$ on both sides of a massless dielectric rod and it starts oscillating due to an external electric field. Other than the external field would there be an electric ...
2
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0
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Magnetic field due to a double tape line
I have been asked to calculate the inductance of a double tape line :
Now we know that $$ N\phi = LI$$
So let's calculate the magnetic field by assuming an amperian loop like this:
$$\int B.dl = ...
- 361
2
votes
0
answers
406
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Derivation of Coulomb's law from classical field theory
In the section on Coulomb's law in QFT by Schwartz, he expands $-\frac{1}{4}F_{\mu\nu}^{2}$ to get $-\frac{1}{2}(\partial_{\mu}A_{\nu})^{2} + \frac{1}{2}(\partial_{\mu}A_{\mu})^{2}$, can someone ...
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132
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Input impedance of a line with complex load
I am currently studying electromagnetism mostly with the help of the book "Microwave Engineering" and when trying to solve problems which main goal is to compute the input impedance of a lossless ...
- 121
2
votes
1
answer
69
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Faraday Tensor quadruple product
I would like to compute the following:
$$F^{ab}F_{ac}F_{bd}F^{cd}$$
Is this equal to $4(E^2-B^2)^2?$
If so how can i quickly calculate it as such?
- 1,488
2
votes
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How to prove this matrix differential for Born-Infeld theory?
Consider the Born-Infeld Lagrangian, page 30 of Born-Infeld Action and Its
Applications by Cong Wang.
$L_{BI} = \sqrt{\det (1+ F)}$ where $F_{\mu \nu} = \partial_\mu A_\nu - \partial_\nu A_\mu$. I ...
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2
votes
3
answers
823
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Why does voltage cancel out if a circuit is going through a magnetic field?
The answer says that there is no current as there is no voltage, but why is there no voltage even though they cut field lines?
EDIT; I found the answers, but still not really understanding it
- 157
2
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0
answers
102
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Possible Magnets
Okay so I was going through my book and found this interesting question --
Which of the following is possible?
$a)$ a magnet with no poles
$b)$ a magnet with two poles
$c)$ a temporary magnet ...
- 174
2
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answers
154
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One from Landau's Minimum (Macroscopic Electrodynamics)
A dielectric
sphere with the electric and magnetic susceptibilities ε1 and µ1 is rotating with
angular frequency ω in a constant electric field E~ in a medium, characterized
by the parameters ε2 and ...
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2
votes
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answers
208
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Second-order correction in Quantum-Confined Stark effect
In the wikipedia article, there is a second-order correction in the Quantum-Confined Stark Effect. I could not understand how it was solved. I did not understand the meaning of 2(0) and 1(0) and how I ...
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492
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Motion of a charged particle in a "solid" charged sphere (accounting for radiation)
Consider a particle (point charge) with charge $q$ and mass $m$ that crosses into a uniformly charged sphere (with charge $Q$ and radius $R$). The trajectory of the particle is a diameter of the ...
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480
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Magnetic flux density a small distance off axis from a current loop
I'm currently studying physics at University and struggling with the problem mentioned, it's on a past paper I'm trying to do.
I have calculated the B field on axis as (sorry don't know how to format ...
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