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.
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Warpdrive while staying stationary nonbending of space [closed]
Core Observations & Theoretical Foundation:
Solar Emission + Cosmic Magnetic Fields:
Yes, the Sun emits charged particles (solar wind), and interstellar magnetic fields are very real.
Voyager 1 &...
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If a large enough electron beam accelerates enough, will its induced electric fields, stop it?
Given acceleration of a beam of charges, there should exist a changing magnetic field around a beam of charges. That changing magnetic field is equal to the negative curl of the induced electric field....
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Exergy of EM radiation
I understand that the usable energy of a high-temperature region depends on the low-temperature region you dump waste heat into - the lower temperature your sink, the less of your energy you have to ...
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How would a purely classical universe be perceived? [closed]
Imagine a hypothetical universe whose underlying fundamental laws were classical. What would that universe 'look' like from an observer in that universe?
In classical mechanics we often take for ...
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Pulse wave paradox [closed]
An oscilloscope picks up a sound with a dynamic microphone. The display shows a pulse wave that is up 10% and down 90% of the cycle each time with an equal but opposite voltage. The question is, what ...
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Energy-momentum Tensor in QED
I've been attempting to 'derive' electromagnetism for a classical Dirac field by imposing local U(1) invariance of the Lagrangian density. This has gone well and good, but I've since tasked myself ...
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How sensible is this toy model for an AC generator? [closed]
This may be more relevant in the Engineering SE, but I believe it is appropiate in this forum since it is mostly about modeling physical systems - not about actual AC generators.
Consider a simple ...
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Why does a constant vector potential along a circular direction have this form? [closed]
My question comes from page 202 in the book "String theory and M-theory" by Becker-Becker-Schwarz. In Exercise 6.2 in this page, the author says:
"Consider a relativistic point ...
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Why do we take the RMS when talking about the effective voltage of AC instead of taking the mean of $|V(x)|$?
When we talk about the effective voltage of AC, we take the Root-Mean-Square, which ends up being $V_{peak} / \sqrt{2}$ for sine wave energy supplies.
Why do we not just take the average value of the ...
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Change of phase due to electric potential
In Volume II of the Feynman Lectures, in this section, he is talking about how the magnetic vector potential $\boldsymbol{A}$, defined by $\boldsymbol{\nabla} \times \boldsymbol{A} = \boldsymbol{B}$, ...
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Does Charles Kittel's explanation of the canonical momentum in an electromagnetic field sense?
In appendix G of Charles Kittel's book on the introduction into Condensed Matter Physics an explanation of the canonical momentum in an electromagnetic field is provided:
The motion of a charged ...
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How can one practically measure electrostatic potential differences in a circuit when there's a varying magnetic flux?
Suppose we have an electrical circuit in the presence of a varying magnetic field. As in https://physics.stackexchange.com/a/847326/404476, we define the electrostatic potential at a point $\mathbf{x}$...
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Can we think of magnetic monopole as something that exists in a higher dimension? [closed]
I understand the following might seem daunting and confusing, but believe me if you watch the video segment and think deeply, you'll find my question reasonable. I apologize for not being able to ...
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System symmetries and electric field direction [closed]
I am a physics student. I am currently taking an introduction to electromagnetism. I would like to understand more rigorously the connection between system symmetries and (in this case) electric field ...
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Mathematical incongruency on integral form of Lorentz force law
I'm a physics student. I'm currently taking an introductory course on electromagnetism. My book (Corrado Mencuccini - Vittorio Silvestrini, electromagnetism and optics, I've translated the title from ...
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