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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Transverse current equivalence in Coulomb gauge
I have a question concerning transverse (solenoidal) current in the Coulomb gauge. This current is the one that enables the radiation, since we have a wave equation for the vector potential:
$\nabla^...
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Why electromagnetic waves propagating along x transfers to electron momentum along z?
Why EM waves having only x momentum transfers to electron z momentum? Electron begins oscillating along z, so will not radiate EM waves along z direction, to compensate its z momentum. It seems that ...
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Field created by varying Gravitational field
Changing Electric Field causes Magnetic filed and changing Magnetic Field causes Electric Field. Is there anything similar in relation to Gravitational Field? What sort of field is created by varying ...
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Gravititonal fields compared to electromagnetic fields - are they infinite in range?
me and my friend has a discussion last night, and he argued that both an electromagnetic field and gravititonal field are infinite in their area of effect, but with diminishing effects as you get ...
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Magnetic susceptibility in 1/eV
In this paper the authors refer to
transverse susceptibility $\chi_{ \perp}$ [meV $^{−1}$]
I was taught that the magnetic susceptibility is dimensionless.
How do I get $\chi$ in the above units??
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Ground-based anti-matter detector on the cheap?
Given today's revelation of the detection of terrestrial gammay-ray flashes (TGF) produced by thunderstorms and the associated pair production of an electron and a positron, how feasible is it to set ...
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What happens when two smooth surfaces touch?
I am wondering what will be the physics to explain how two neutral, chemically nonreactive objects stick. I know that using van der Waals formalism, we can treat neutral body electrodynamic forces and ...
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How does capacitance work?
I have a circuit whit a AC source a capacitor and a resistance all in series. I find that the difference of potential between the capacitor leads begin to change after some instants as it should. But ...
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Degenerated Anderson Model Simulation
I'm trying to simulate the degenerative Anderson model. So depending on an energy difference first orbital and afterwards spin magnetism occurs. First i try to solve an easier ansatz with a limitation ...
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Using the Scalar Electrostatic Potential to Calculate Transition Probabilities
transition probabilites of atomic systems prone to some time-varying electromagnetic field are very often calculated using perturbation theory leading to expressions including the vector potential $\...
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Electric potential energy in curved space-time
In flat space-time the electric potential energy between two charges is $\frac{k Q_1 Q_2}{r_{12}}$, where $Q$'s are charges and $r_{12}$ is the distance between them. What would happen if the two ...
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Sum of angular momentum of all electrons in a magnet
Can the sum of angular momentum of all rotating electrons in all the aligned atoms in a permanent magnet have a significant contribution to the macro angular momentum of the magnet? If yes, why does ...
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Measuring the vacuum permittivity
So I was reading the EF experiment that's used at the MIT to measure the vacuum permittivity and I was thinking about trying it just to see how it works:
http://ocw.mit.edu/courses/physics/8-02x-...
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Experimental evidence showing the kinetic energy of an electron changes in a static non-uniform magnetic field?
In a previous question, Does a magnetic field do work on an intrinsic magnetic dipole?, one highly rated answer suggested that static magnetic fields do work on intrinsic magnetic dipoles in a non-...
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What stochastic process is associated with spontaneous electromagnetic radiation?
Imagine one have an ideal sensor, which can convert the emission to some kinds of signal (typically, voltage, and suppose no noise at all), then what process can describe the measure data? Is it ...
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