All Questions
Tagged with electromagnetism inductance
44
questions
58
votes
7
answers
21k
views
Cyclist's electrical tingling under power lines
It's been happening to me for years. I finally decided to ask users who are better with "practical physics" when I was told that my experience – that I am going to describe momentarily – prove that I ...
- 180k
21
votes
4
answers
41k
views
Derivation of self-inductance of a long wire
Currently I am stuck, trying to derive the self-inductance of a long wire. According to literature it should be
$$L=\frac{\mu_r\mu_0l}{8\pi}$$
and in literature its derived by looking at the energy ...
- 1,573
18
votes
3
answers
11k
views
Faraday's law - does the induced current's magnetic field affect the change in flux?
I've had this conceptual problem with Faraday's law and inductance for a while now.
Take the example of a simple current loop with increasing area in a constant field (as in this answer). So Faraday'...
- 533
10
votes
4
answers
4k
views
Where does the extra energy come from in an LC circuit?
In an LC circuit, or an LC tank, the capacitor discharges in one direction
through an inductor and then the inductor seems to carry energy in the form of a magnetic field , to charge the capacitor ...
- 607
3
votes
1
answer
3k
views
Magnetic Flux conservation
My teacher said that after switch is shifted (after very long time), $\phi_i = \phi_f$ $\implies i_oL = i3L \implies i = \dfrac{i_o}{3} $ where $i_o$ is $\dfrac{\varepsilon}{R}$
So the initial ...
- 375
1
vote
3
answers
319
views
Significance of sliding switch in a LR circuit
The following image and statement are from my textbook Concepts of Physics on the chapter "Electromagnetic Induction", topic 38.6 "Growth and decay of current in an LR circuit", ...
- 5,306
1
vote
2
answers
2k
views
What is the magnetic flux density "outside" the solenoid when AC current is passing through it?
I know that there are well defined equations explaining the magnetic flux density in the solenoid.
However what about magnetic field outside the solenoid?
How is the magnetic flux density related ...
- 111
1
vote
1
answer
822
views
Differential equation in RL-circuit
I am self-studying electromagnetism right now (by reading University Physics 13th edition) and for some reason I always want to understand things in a crystalclear way and in depth. Now look at this ...
0
votes
2
answers
444
views
The direction of induced electric field around a changing current wire
I saw in my textbook that the induced electric field around a changing current wire is parallel to the direction of the current, for example:
Why is that?
Thanks!
10
votes
5
answers
10k
views
Magnetostatic energy density -- derivation without introducing inductance?
I was looking for a derivation of the expression for the energy density at any point in a static magnetic field. I do know that it is
$$u_B=\dfrac {1}{2 \mu_0}\left|\mathbf{B}\right|^2,$$
I was just ...
- 625
1
vote
2
answers
144
views
Inductor with ac supply
When an ac source is connected with an inductor we have a continuous change in voltage and current across the inductor.
According to farady and lenz law we will get an equal and opposite voltage ...
- 1,441
1
vote
1
answer
2k
views
Does the direction of magnetic field in a solenoid point from north to south anywhere? [closed]
Is there any case where the direction of magnetic field inside a solenoid points from its North Pole to its south?
- 187
1
vote
2
answers
400
views
How to calculate flux in a helical wire?
We have a wire going around in a helix (just like an inductor) and a constant magnetic field exists along its axis throughout the space.
How do we calculate the flux through it? I can't understand ...
- 1,260
1
vote
1
answer
831
views
Is a unit coupling coefficient for mutual inductance (so $M=\sqrt{L_1L_2}$) compatible with different self-inductances $L_1\neq L_2$?
We considered mutual inductance in my lectures and the definition $M=k\sqrt{L_1L_2}$ where the coupling constant $k$ can vary between 0 and 1. When covering transformers, my lecture notes "assume that ...
- 3,997
0
votes
0
answers
111
views
How to find the canonical equations of the RLC circuit
First, I consider the LC circuit with an ion in the capacitor, which is like this:
The current $I$ can be derived easily by using Shockly-Ramo theorem
\begin{equation}
I = -\frac{qp}{dM} + C\dot{U} \...
- 68