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.
68 questions from the last 30 days
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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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1answer
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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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1answer
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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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Electrostatic generator,why they don't exist? [closed]
Suppose we have a two metallic plates separated by a dialectric medium inside a changing electric field.This according to Maxwell's equations will generate a electric current as opposed to generators ...
- 173
2votes
1answer
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Polarization ellipse - Relating the ellipticity angle to the field parameters
I am working through Zangwill's Modern Electrodynamics. In section 16.4, he presents two results that relate the polarization ellipse's orientation angle ($\alpha$) and ellipticity angle ($\gamma$) to ...
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Can we make marine-propeller-like antenna: generating positive and negative radiation pressure?
In hydrodynamics there is marine propeller generating positive and negative pressure (image source) thanks to tilted blades. Electromagnetism and hydrodynamics are very similar mathematically ( https:/...
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Stress-energy tensor of Maxwell's theory in 4d curved spacetime
If we consider Maxwell's theory in 4d curved spacetime, the action is(in natural units): $$ S=\int\sqrt{-g}\left(-\frac{1}{4}F_{\mu\nu}F^{\mu\nu}+A_\mu J^{\mu}\right)\mathrm{d}^4x=\int\sqrt{-g}\...
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Intuitive explanation for the boundary conditions in Maxwell equations [duplicate]
I was looking into the Maxwell equations and was trying to get an intuitive understanding of why there is a difference between the normal and tangential field components. Is there an explanation that ...
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1answer
81views
Unification of Electric and Magnetic Forces
I'm trying to re-learn special relativity -- PhD in physical chemistry 50 years ago. In "Special Relativity for Beginners" by Jurgen Freund,p. 29, it states: "A copper filament ...
1vote
1answer
79views
Resultant Inductance of inductors in parallel
I learned that when two coils of inductance $L_1$ and $L_2$ of mutual inductance $M$, and they aid each other magnetic field, are in parallel, the resultant inductance is: $$L_{eq} = \frac{(L_1*L_2-M^...
