All Questions
Tagged with physics electromagnetism
101
questions
3
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0
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80
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Rutherford Scattering - Annular Detector in the Far Field [closed]
I have been tasked to find the rate at which scattered electrons will be detected on an annular detector in the far-field. The exact question I'm working with is:
Suppose that 1keV electrons, ...
- 1,021
5
votes
1
answer
569
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Deriving analytic expression for magnetic field & flow lines of bar magnet.
How can we analytically derive the flow-lines of a normal permanent bar-magnet?
Physics context & own approach:
In classical electromagnetics we have the legendary Maxwell's Equations:
$$\begin{...
- 26.1k
1
vote
1
answer
251
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Computing (distributional) gradient of a singular function
This question could well belong better to the physics stackexchange, but I'm hoping that posting it here could give me a more mathematical perspective.
I am trying to find the expression for the ...
- 1,183
0
votes
1
answer
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Normalising angled Earth magnetic field
Me and my team are participating in ESA Astro Pi challenge. Our program will ran on the ISS for 3 hours and we will our results back and analyze them.
We want to investigate the connection between ...
- 101
3
votes
2
answers
94
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Can we motivate mathematically why wind turbines almost always have 3 flappers and aeroplane propellers can have any number of flappers?
Firstly I know some might frown upon a question so very broad and applied as this one. It really may not be a well defined mathematical question as some people would prefer on the site. I am okay with ...
- 26.1k
2
votes
1
answer
87
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How to find the critical point for this Coulomb field
Two equal positive charges are at distance $d$, $-d$ from the origin on the $y$ axis. What is the distance on the $x$ axis beyond which a small perturbation in $y$ will move a particle away from the $...
- 1,552
4
votes
1
answer
412
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solution to $\square\chi=f$.
For an open set $U \subseteq \mathbb{R}^4$, if $f:U \to \mathbb{R}$ is a "good" (for example, smooth) function, is there a solution to the following equation?
$$\left( \Delta - \frac{1}{c^2}\frac{\...
user53216
0
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Use $\nabla\times(f \vec A)=\nabla f \times \vec A + f (\nabla \times \vec A)$ to rewrite Faraday's law as $\omega \vec B_0=\vec k \times \vec E_0$
We may represent a general electromagnetic plane wave by (real part of the complex exponentials):
$$\vec E = \vec E_0\exp(i\vec k \cdot \vec r - i \omega t) \quad\text{&}\quad\vec B = \vec B_0\...
- 8,528
4
votes
2
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Gauss' law and a half-cylinder
The question is:
A half cylinder with the square part on the $xy$-plane, and the length $h$ parallel to the $x$-axis. The position of the center of the square part on the $xy$-plane is $(x,y)=(0,...
- 75
2
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0
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257
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What is the relation between 2d Fourier Transform and Plane Waves? [closed]
I'm not understanding how the two was related, but I was told that the 2d Fourier Transform decomposes an electromagnetic signal into plane waves. This, however, I am not understanding. I thought it ...
- 3,405
0
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2
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130
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Calculation of capacitance between two cylinders
I'm trying to calculate the capacitance of two circular cylinders (it's a coil). I'm ok with the physics but I'm stuck in a point of the calculation. I have a complex function which contains the ...
1
vote
1
answer
195
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Electric field above polygonal loop in the limit to circular loop
The electric field at a point a distance $z$ above the midpoint of a segment of length $2L$ and uniform charge density $\lambda$ is given by
$$\mathbf{E} = \frac{1}{4\pi\varepsilon_0}\frac{2\lambda L}{...
- 7,532
3
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0
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130
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Radial fourier transform of gaussians
In this paper is calculated the square modulus of the radial fourier transform of the function $\rho(r)$
$$\left|F(q)\right|^2=\left| \int_{\mathbb{R}^3} e^{i\mathbf{q}\cdot\mathbf{r}}\rho(\mathbf{r})...
- 275
1
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1
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292
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How to show that $E_\theta=-\frac{\partial V}{r \partial \theta}$
How to show that $$E_r=-\frac{\partial V}{\partial r}$$ and $$E_{\theta}=-\frac1r \frac{\partial V}{\partial \theta}$$
where V is the potential at the point $(r,\theta)$ of the dipole.
I can take ...
- 1,164
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0
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139
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Why is the electric field of a naturally equilibrating, isotropic, cylindrical conductor not a function of z (height)?
Some math is presented below to make the question more specific.
TL;DR: If you calculate the electric field of a solid, cylindrical conductor, you find that this field is only a function of radius ...
user213745