All Questions
31
questions
1
vote
2
answers
4k
views
Biot-Savart law and magnetic field of a ring
I have to calculate the magnetic field along the axis of a ring of radius $R$ on which circulates a current $I$ using the Biot-Savart law. The Biot-Savart law as given in my (really bad) course states
...
- 4,736
2
votes
2
answers
569
views
Find torque due to Lorentz force - Wrong result [closed]
Current I is coming from the Z axis and then it flows out uniformly towards the circumference of this disk. The disk has thickness t and Radius R. There is also a constant B field in the Z direction(...
- 351
4
votes
1
answer
3k
views
Finding the vector potential of a spinning spherical shell with uniform surface charge?
I have problem solving the following magneto-static problem. I would greatly appreciate help and guidance.
This is how the problem is stated:
A spherical shell of radius $R$, carrying a uniform ...
- 1,135
13
votes
2
answers
5k
views
Deriving Biot-Savart Law from Maxwell's Equations
As an exercise, I've been trying to derive the Biot-Savart law from the second set of Maxwell's equations for steady-state current
$$\begin{align}&\nabla\cdot\mathbf{B}=0&&\nabla\times\...
- 838
0
votes
1
answer
856
views
Induced current in a circular loop [closed]
In this question I tried using right hand thumb rule for long wire to get magnetic field into plane of paper which induces clockwise current in Loop,again by thumb rule. The problem arises when force ...
6
votes
2
answers
2k
views
Derivation of Ampere's Law in Jackson
The derivation of Ampere's Law in Jackson E&M from the Biot Savart law is for the most part fairly traditional, using the $\nabla\times(\nabla\times A)$ identity on the vector potential:
$$\nabla\...
- 838
3
votes
2
answers
2k
views
How can we apply Ampère's circuital law in a wire?
How can we apply Ampere's circuital law in a wire to calculate magnetic field around a straight current carrying wire? The length of the wire is not infinite.
Using the Biot-Savart law we get
$$B = ...
- 2,091
1
vote
2
answers
2k
views
How to get image current in magnetostatics? (magnetic slab)
I want to know the image current and its location which satisfies the boundary condition at the interface.
This problem was originated from the problem 6-33 in Fields and wave electromagnetics, D. ...
- 209
0
votes
1
answer
1k
views
Magnetic field between two rings [closed]
Two rings are placed parallel atop each other along an axis with a distance $\epsilon$ which is much smaller than the radius of both rings a. Through one of the rings there is a current I and through ...
- 41
0
votes
1
answer
2k
views
The magnetic field between two intersecting cylinders [closed]
Consider a cable of infinite length whose section has the form of two intersecting circles of same radius $a$. The first part is then a cylinder of constant volume current density $J$ along the ...
- 183
0
votes
1
answer
2k
views
Magnetic Field Along the Axis of the Current Ring - Alternative way to compute
This is Example 5.6 in Griffith's Introduction to Electrodynamics (4th Edition):
Find the magnetic field a distance $z$ above the centre of a circular loop of radius $\ R$, which carries a steady ...
- 3,719
0
votes
1
answer
2k
views
Finding the vector potential of an infinite cyclinder with uniform surface current
This is the second part of a problem in Griffith's "Introduction to Electrodynamics 4th Edition" (problem 6.16).
The first part was to find the magnetic field inside a coaxial cable (2 concentric ...
- 342
1
vote
1
answer
1k
views
How do you show that the normal derivative of the magnetic vector potential is discontinous across a surface current?
This is from Griffith's "Introduction to Electrodynamics" 4th edition, problem 5.33.
I need to show that
$$
\tag 1 \frac{\partial \textbf{A}_{above}}{\partial n}-\frac{\partial \textbf{A}_{below}}{\...
- 342
3
votes
2
answers
705
views
Challenging Magnetostatics Problem - the "blind spot" of a magnetic dipole
I'm reviewing for an electromag exam and I stumbled upon a problem that's really hard to figure out. Here it is:
A small magnetic dipole with moment $\vec m = m_o \hat z$ is in a region with uniform ...
- 197
2
votes
1
answer
8k
views
Magnetic field of uniformly charged rotating hollow sphere
I want to compute the magnetic field due to a homogeneously charged, rotating sphere with radius $R$, angular velocity $\vec{\omega} = \omega\hat{z}$ and total charge $Q$. I want to use Biot-Savart ...
- 356