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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What are the operators here and how are these formulas derived? [closed]
In (23), are grad and div some kind of scalar operators comparing to $\nabla$ and $\nabla\times$? because tbh I dont know how $\text{curl}(\mu^{-1}\text{curl}\textbf{A})$ turns into $\text{div}\mu^{-1}...
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Comparing Electric Potential Energy of two Charges
I do not know what I am missing here and would appreciate a little help in figuring out the flaw in my logic. I have a row of positive charges and a row of negative charges as shown in the image above....
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Voltage: work to move a charge, or difference of electric potential?
Let's say I have a single positive charge inside of an electrostatic field. I want to move this charge from point A to point B and determine the voltage between the two points.
Points A and B are the ...
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What is the impressed current density?
I don't have a too solid background for physics and am reading some engineering books of electromagnetics. What is the impressed current density here? I think it is Ohm's law but couldn't find its ...
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Effects of Localized Medium Changes on Field Propagation
I've studied various theories related to fields. These theories often include equations describing how the activity of a source is transmitted to other locations. The properties of the medium ...
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What is the best way to remove static from an FM radio [closed]
So, I don't have much of a background in electricity and electromagnetic phenomena, but I had always had a knack for tinker with things with a bit of logic to make them work. So, I was wondering if ...
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Calculation of magnetic vector potential A in FEMM [closed]
I don't have too much physics background. In the software FEMM, I simulated a closed loop magnetic circuit, and defined two current boxes (current density is uniform by default) on the left. The ...
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Most generic form of refractive index tensors
The refractive index of a material is in general a $3x3$ tensor (as in the case of birefringent crystals). From literature, it seems that in the case of transparent crystals, this tensor is in general ...
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Why the $T_1$ recovery & $T_2$ decay are independent?
In MRI, I was thinking that the decrease in transverse magnetization results in the recovery of longitudinal magnetization.
However, recently, I found it was wrong. I saw a diagram
(McRobbie 2014. ...
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Rotating Tank of Charged Liquid
Consider a long rectangular tank of dimensions a×b, where a≫b, that is rotating at a constant angular velocity and filled with an incompressible charged fluid. How would one find an equation ...
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How to calculate the magnetic field of a coil? [closed]
I want to find a formula for the magnetic field of a coil in some random point outside of the coil. I understood that I must use the Biot-Savart's law and integrate first over one loop of the coil, ...
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Length of helix in one time period [closed]
How to find the length of a helix in one time period?
In the case of a particle suspended at the origin and a magnetic field along the $y$ axis we know that the time period will be equal to $2\pi/aB$ ...
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Straight wire in moving uniform magnetic field induced emf
My question is a follow-up to this one.
The green dotted line is the arbitrary loop which is constructed in the calculation of emf in the wire of length L. x is a variable which can be changed to ...
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Can a satellite generate electricity by using a planet's magnetic field? [duplicate]
I am entering AP Physics E&M and don't have much knowledge about electricity but always had an idea based on my limited knowledge.
If a satellite had a metal coil inside of it, wouldn't it have an ...
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What happen when a circular coil (not a rod) is moving in a uniform magnetic field that is perpendicular to the velocity with which it is moving? [closed]
B is perpendicular to v
Conductor is in circular shape which is moving with v velocity in the Uniform magnetic field B
