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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The puzzling interaction between an anapole moment and external fields
Consider an electrical current distribution with only an [anapole, or toroidal moment] but no electrical or magnetic multipole moments, like this current on a torus:
Its magnetic field is completely ...
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Why is Biot–Savart law and Ampère's law different in my scenario?
If I consider a finite length of wire in which current I is flowing. if I consider a circular loop above the finite wire, such that the current passing through that circular loop is zero.
According to ...
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Force b/w current carrying loops
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In the figure shown the rings are carrying currents in same sense. In this situation there is no interaction between them but if they were carrying current in opposite sense would they repel each ...
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Relation between Earth's and Sun's magnetic axis relative to their paths of travel and relative to each other?
Pretext
As non-educated citizen with no academic background, and based on watched PBS Space Time's latest video I've got curious, what's the relation between Earth's and Sun's magnetic axis relative ...
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Is charge an intrinsic property of matter? [duplicate]
Is charge an intrinsic property of all the particles that comprise matter or is it an intrinsic property limited to certain fundamental particles only??
Or the question can be revised as "Does ...
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Magnetic energy associated with an intrinsic dipole
Generally for an Amperian dipole we have:
Magnetic energy when it is placed in a uniform magnetic field is $\vec m \cdot \vec B$.
We can define "a fake kind of energy" [Feynman] that can ...
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Lienard's Formula from the Larmor Formula and Relativity
I am trying to understand the solution to exercise 12.71 in the document linked below which accompanies Griffith's book on electrodynamics. The problem states that we are to use the Larmor formula and ...
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How come the magnetic field disappears when a neutron star becomes a black hole, while the rotation remains?
The only question I found is this one, but this considers as non-rotating neutron star collapsing:
Our final and most comprehensive test is represented by the collapse to a BH of a magnetized ...
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Why is induced EMF in DC motor being included in Kirchoff's Loop Rule
I was reading some lecture notes (don't think I can include them here) that show the EMF induced in the armature of a DC motor, being included in the equation of Kirchoff's Voltage Law for the ...
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Uniqueness of Maxwell Lagrangian: Why does it not include the term $c_3 (\partial_\mu j_\nu)F^{\mu \nu}$?
In the textbook Condensed Matter Field Theory by Altland and Simons, it is said that the Maxwell Lagrangian $\mathcal{L}$ coupled to a four-current $j^\mu$ satisfying $\partial_\mu j^\mu = 0$ is the ...
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Is there a second-order non-linear addition to Maxwell's equations?
Maxwell's equations are famously linear and are the classical limit of QED. The thing is QED even without charged particles is pretty non-linear with photon-photon interaction terms. Can these photon-...
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Bethe diffraction: surface charge density of an ellipsoid
I'm having a hard time following one part of Bethe "Theory of diffraction by small holes" paper, which can be found here: https://web.stanford.edu/class/ee349/Handouts/Bethe_PR1944.pdf
At ...
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Why should an electron falling into the nucleus, according to the Maxwell's laws of electrodynamics, destroy the atom?
It is often said in physics and chemistry classes and textbooks that atoms must be unstable when the electron continuously loses energy and finally fall into the nucleus according to classical physics....
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What happens when both magnetic field and electric field is applied to a charged particle?
Now what exactly happens when magnetic field and electric field is applied perpendicularly? What happens when they are not perpendicular?
In the question, it says that a magnetic field and electric ...
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How can the current be sustained in a tethered satellite system?
I have a question about how the current is sustained in a tethered satellite system TSS-1R.
In the most simplified model, the system is basically a straight wire (connecting the shuttle and satellite) ...
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