All Questions
127
questions
3
votes
0
answers
52
views
Question about Fourier-coefficients in Griffith's Problem 3.15 (Electrodynamics) [closed]
I am having some trouble with problem 3.15 from Griffith's Electrodynamics. It states the following:
A rectangular pipe, running parallel to the $z$-axis (from $-\infty$ to $+\infty$), has three ...
- 49
0
votes
0
answers
31
views
Need help identifying missing boundary condition in charge transport problem
The system I am considering consists of a conducting liquid sandwiched between two electrodes.
The electrodes supply a constant flux of electrons $J_{ext}$.
In the liquid there are also uncharged ...
- 33
0
votes
1
answer
34
views
How to find the capacitance between two metal sheets [closed]
Let’s say I have two metal sheets in a 2D plane. The first one has area A, the second one is infinitely long, and they are separated from each other by a distance d. How can I find the capacitance ...
1
vote
1
answer
62
views
'Thin' conducting plate ambiguity
The situation at hand:
We have an infinite, thin conducting, grounded ($V=0$) plate at $z=0$.
Point charge (with charge +$Q$), at $z = a$.
How exactly are the charges distributed? I used the method ...
1
vote
1
answer
63
views
Derivation of the ring charge from a disk charge with a hole
I am doing a problem in which I am given a uniformly charged disk, charge density $\sigma$, with radius $b$ and a concentric hole of radius $a$ in the $xy$ plane. A part of the problem I would have to ...
- 11
-1
votes
1
answer
44
views
Is the strength of the charge equal on all points on an equipotential surface? [closed]
Since the equipotential is calculated by $V = q\cdot \frac{k}{r}$ I suppose that the charge is the same at any point on an equipotential surface but I'm not sure.
0
votes
1
answer
115
views
Point charge between two infinite dielectrics [closed]
Two infinite linear homogeneous and isotropic dielectrics $\epsilon_1$ , $\epsilon_2$, occupy the regions $z>0$ , $z<0$ respectively. A point charge q is located at the origin. By applying the ...
- 3
1
vote
1
answer
93
views
Prove that the electrostatic potential is zero (Wald) [closed]
Let $V$ be a bounded region of space and let $\phi $ be an electrostatic potential that is source free in this region, so that $\nabla^2 \phi=0$ throughout $V$. Suppose that $x$ is lying on the ...
- 76
0
votes
1
answer
47
views
Trying to find the magnetic force applied by an infinite wire on a circuit both carrying different currents
The problem I'm trying to solve is:
We have:
An infinite wire carrying the current I and creating the magnetic field: $\vec{B}(M) = \frac{\mu_0I}{2\pi\rho}\vec{e}_{\phi}$
A square shaped loop ...
0
votes
1
answer
123
views
Force exerted by the southern hemisphere of a uniformly charged sphere on the northern hemisphere
I understand that this question has been asked multiple times before but my question is regarding something specific.
I came across the following solution on the web:
Since $\vec{E}$ is the field at ...
- 1,640
0
votes
1
answer
109
views
Multipole expansion along a ring [closed]
I'm supposed to calculate the behavior of the electrostatic potential $V$ at large distances $|r| \gg a$ for the following linear charge density along a ring of radius $a$:
$$\rho(r,\psi, z) = \frac{q}...
- 287
2
votes
1
answer
839
views
What will happen to the bulb of the circuit after closing the switch? [closed]
Say it connects a bulb with the circuit below, with the switch $S$ open. Every cable has negligible resistance and the battery has no internal resistance.
What happens to the brightness of the bulb ...
- 23
0
votes
1
answer
29
views
What is the intuition for no resistance between concentric spherical surfaces if $k = 0$ in this problem? [closed]
I've currently solved problem 5.16 in Cheng's book on Field and Wave electromagnetics. The problem is stated as:
Determine the resistance between two concentric spherical surfaces of radii $R_1$ and $...
- 344
1
vote
1
answer
57
views
Determine the charge distribution and the total charge of the system [closed]
Suppose we have a spherical symmetrically distributed charge in vaccuum which yields us a spherically and symmetrical potential $V(r)$ according to:
$$V(r) = V_0(1-(r/a)^2)$$
for $r\leq a$ and $0$ ...
- 344
-1
votes
1
answer
92
views
No limits of integration for electric field integral?
For this problem,
The solution is,
However, why have they not included limits of integration? I think this is because all the small charge elements dq across the ring add up to Q.
However, how would ...
- 49