All Questions
24
questions
9
votes
6
answers
7k
views
Are the field lines the same as the trajectories of a particle with initial velocity zero?
Is it true that the field lines of an electric field are identical to the trajectories of a charged particle with initial velocity zero? If so, how can one prove it?
The claim is from a german ...
- 191
4
votes
4
answers
5k
views
What is the *cause* of the Lorentz Force
Is it possible to explain what actually causes the force on a current carrying conductor in a magnetic field. I have read that this is due to the magnetic fields 'interacting' in some way.
This ...
- 195
3
votes
3
answers
149
views
Shouldn't We modify the field in force equation $\mathbf{F}=q\mathbf{E}$?
Consider charge particle $q$ in electric field $\mathbf{E}$. The force on the charge is given by
$$\mathbf{F}=q\mathbf{E}$$
Now we know that charge $q$ will also produce an electric field. Due to this ...
- 11.9k
3
votes
1
answer
302
views
High Level Understanding Q: What *is* a magnetic/electric field?
Note: I have seen this question -> (What is a magnetic field) and would still like some clarification.
I have also seen https://www.youtube.com/watch?v=hFAOXdXZ5TM and https://www.youtube.com/watch?...
- 145
3
votes
3
answers
630
views
How and in what way do force fields work and exist?
Do fields constantly exist with their sources, for example, will a positive charge keep exerting a positive electric field irrespective of whether we put a small positive or negative charge nearby/...
- 31
2
votes
2
answers
1k
views
Similarity between electromagnetic waves $E/B=c$ compared with the equality between Lorentz force and electric force
I am very tired and in this moment I have not think very well. Using the vectorial expressions of the magnetic and electric field if an electromagnetic wave propagates in a certain direction the ...
- 2,547
2
votes
3
answers
827
views
Using newton's third law in electromagnetism and special relativity problems
I am confused with using newton's third law in electromagnetism problems which includes Lorentz transformation.
In what conditions does this law holds?
for example, if there is an infinite charged ...
- 23
1
vote
1
answer
159
views
Electric field on test charge due to dipole
In worked example 4.1 of Intermolecular and Surface Forces by Jacob Israelachvili, he is calculating the electric field on a test charge due to the dipole shown in the picture.
He assumes $r\gg l$ and:...
- 261
1
vote
2
answers
86
views
About fundamental physics (static fields, forces, and energy)
Disclaimer, so that you can provide a more informative answers: I have a degree in mathematics but I am quite ignorant in physics.
I was reflecting about the ability of a charged particle (any ...
- 194
1
vote
1
answer
296
views
Electric force in general relativity
In general relativity, for two electrons in a space-time how do we define the electric force? Is it such that we have in classical physics or they go away from each other because of the curvature that ...
- 39
1
vote
1
answer
61
views
The force experienced on a charge, using macroscopic quantities
Zangwill says (Zangwill, Modern Electrodynamics, 2012 edition, page 40, undersection 2.3.1, "Lorentz Averaging")
...An example is the force on the charge density $\rho$ and current
density $...
- 702
1
vote
1
answer
132
views
Ratio between electric and magnetic forces
Suppose I have two beams of electrons moving at speed $v$ separated by a distance $d$. I can work out magnetic and electric forces between them...
For the magnetic force, we treat the two beams wires ...
- 2,456
0
votes
2
answers
64
views
Why can we add the two terms in the Lorentz force?
The term "Lorentz force" in the title refers to (1).
my textbook states:
The Coulomb force is mediated by the electric field and acts on the charge $q$, that is, $\mathbf{F}_e = q\mathbf{E}$...
- 165
0
votes
2
answers
463
views
Electrostatic potential of a dipole in a non-uniform field
There are numerous derivations for the potential energy of a dipole in a uniform field as:
$$
U = - \boldsymbol{p}\cdot\boldsymbol{E}
$$
But does this hold also for non-uniform fields? Are there any ...
- 602
0
votes
1
answer
490
views
Direction of magnetic field lines around a conducting wire
By way of the first uploaded picture I was taught that magnetic field-lines around a long conducting wire with a current are shaped like concentric circles around the wire. However, a few pages ...
- 559