All Questions
43
questions with no upvoted or accepted answers
4
votes
3
answers
351
views
Magnetostatics or dynamics?
A spherical conductor, carrying a total charge $Q$, spins uniformly and very rapidly about an axis coinciding with one of its diameters. In the diagrams given below, the equilibrium charge density on ...
- 1,389
2
votes
0
answers
885
views
Finding the terminal velocity of a magnet dropped in a solenoid
We have to find proportionality of the terminal velocity with the factors of the system:
Plot: a small dipole(mass $m$) with dipole moment $\mu$ is dropped in a long solenoid (radius $r$, ...
- 2,479
1
vote
1
answer
49
views
How can I estimate the force of an electromagnet?
I am doing an experiment on electromagnetism, basically I am just testing the pulling force of an electromagnet using a newton meter with a magnetic hook and seeing how the pulling force changes as i ...
- 11
1
vote
1
answer
96
views
Magnetic Scalar Potential of Infinite Wire
While working on a question about magnetic scalar potential, I encountered a challenge. The question posits that the magnetic scalar potential, denoted as $\phi$, takes the form $\phi = -\frac{I}{2\pi}...
1
vote
0
answers
261
views
Magnetic field due to circular surface current density
I am trying to find the magnetic field between two coaxial cylindrical shells of radius $a$ and $b$ respectively. They have a surface current density of $K = K_0cos(\theta)\hat{\theta}$ and $K=-K_0cos(...
- 324
1
vote
0
answers
22
views
Magnetic field due to a line and a plane
I need to find the magnetic field produced by this arrangement
Let me explain the image: The vertical line is a conducting straight line with a current being conducted. Now, the horizontal line is ...
- 980
1
vote
0
answers
35
views
Two bar magnets taped together in opposite direction (north-south) dropped through a coil
I conducted an experiment where I have to align two bar magnets so that both ends are “north - south” and tape them together. Then, I have to drop them through the center of a coil of 400 turns
...
- 11
1
vote
2
answers
331
views
How to calculate pole strength for this magnet?
I know magnetic mono poles don't exists and a magnetic poles always have equal strength. But what about a magnet which looks like this?
This is picture of magnet whose thickness is constantly ...
- 1,691
1
vote
0
answers
207
views
How to calculate the magnetic field of two cylinders when one of them is rotating
Given is the voltage U and the Angular velocity $\omega$. The rotating cylinder is inside the other cylinder and U is measured between them.
To calculate the magnetic field, I tried to solve
$\oint ...
- 23
1
vote
0
answers
74
views
Magnetism: EMF induced by a conducting balloon filling with water
Info:
As stated in the title, I'm wondering how to find the EMF induced by a conducting balloon. This balloon is under a waterfall, and it expands and contracts as water is filled in it, with a flow ...
- 11
1
vote
0
answers
617
views
When can Laplace equation be used to solve a magnetostatics problem
Intro:
In magnetostatics, working in c.g.s, $\vec{H}=\vec{B}-\frac{4\pi}c \vec{M}$.
We also have $$\vec{\nabla}\times\vec{B}=\frac{4\pi}c\vec{j}$$
$$ \vec{\nabla}\times\vec{H}=\frac{4\pi}c\vec{j}_f$...
- 599
1
vote
0
answers
956
views
Magnetic Field of a Magnetic Dipole (equatorial position)
Suppose that we have a current carrying circular loop, with radius $a$. At large distance $r \gg a$ from centre of loop, this loop acts as a magnetic dipole. We need to find magnetic field of loop at ...
- 319
1
vote
0
answers
674
views
Magnetic field between 4 wires with the same current
if I have 4 long wires with a current I and all of them have the same distance from each other (looked at from the front you'd have a square) shouldn't the magnetic field vanish in the middle of all 4 ...
- 111
1
vote
0
answers
392
views
Attraction between electromagnet and a permanent magnet - at which point is the force the strongest?
You have an air-core inductor with current applied, so that the magnet in the picture will be attracted to it. At what position will the force between the two be the strongest and at which the weakest?...
- 11
1
vote
0
answers
174
views
What is a simple model to find the jump height for the Thomson's Jumping Ring experiment?
I'm trying to devise a basic formula that could give a rough estimate for the jump height reached in the Thomson's Jumping Ring experiment, as detailed here.
However, it's pretty difficult as most ...
- 11