All Questions
26
questions
11
votes
3
answers
9k
views
When mutual inductance is occurring between two coils, is self inductance always occurring in each individual coil?
When a coil connected to an AC generator creates an EMF in another nearby coil (mutual inductance), is self inductance simultaneously occurring in both coils?
- 545
7
votes
1
answer
538
views
Is Back EMF produced in household wires?
Since we use AC for domestic purpose, shouldn't Back EMF (Counter-EMF) be produced in household wires? If yes, then the output voltage in the appliances will be less (that's what my stupid brain says! ...
- 93
6
votes
2
answers
7k
views
How to calculate required current and specifications for a "wet coil" to generate x Tesla of magnetic field?
A water management project requires a "wet coil" (coil will be submerged in aqueous media) designed to generate a steady-state electromagnetic field of adjustable magnetic magnetic flux density at the ...
- 163
2
votes
2
answers
563
views
Why do old transformers make sounds, but new ones don't?
What I think is that maybe insulation is gradually removed between plates, and eddy currents start passing from one plate to another and this produces sound. Am I right?
- 71
2
votes
2
answers
892
views
Finding electric potential via direction of EMF
I was trying to solve this question:
I understand that if the current is increasing leftward, then via Lenz's Law, the direction of the induced EMF will be to the right. Given that I now know the ...
- 137
2
votes
2
answers
6k
views
why does adding loops in a straight wire increase the magnetic field?
I have seen heaps of articles about what happens to the coil and the magnetic field but nothing about why exactly the overall magnetic field increases when loops are added to a straight wire to ...
- 21
2
votes
1
answer
503
views
Inductor rise time and inductor wire length
So here is an interesting question about inductors or coils in general.
Suppose you had a inductor which was 12 inch's in diameter and say 12 inch's in length and has 100 turns of wire. The total ...
- 23
2
votes
1
answer
408
views
Practical physics: where does this current come from?
It's been a while since school and I don't remember the right laws and formulas. So I come here. :)
I've got a power cord extender running from the wall outlet to my washing machine. It's about 3 or ...
- 3,101
2
votes
1
answer
142
views
Does there exist a rigorous general mathematical proof for $M <\sqrt{L_1L_2}$?
Does there exist a rigorous general mathematical proof for $M <\sqrt{L_1L_2}$? Here $M$ is the mutual inductance between two conductors and $L_1$ and $L_2$ are their respective self-inductances. (...
- 261
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
64
views
Can two transformers used to make tesla coils?
Tesla coils seem to perform the same as a transformers: they use two coils and use magnetic field to transfer the energy. Doesn't using two transformers produce the same result? It doesn't seem to be ...
- 31
1
vote
1
answer
288
views
Is this an accurate equation for describing the magnetic force exerted by a solenoid on a ferromagnetic material?
I saw this question, which contained an equation describing the strength of a solenoid:
$$F = (NI)^2\mu_0\frac{\text{A}}{2g^2}$$
where:
$$F$$ is the force the solenoid exerts on a ferromagnetic ...
- 11
1
vote
1
answer
123
views
No inductor - any induced EMF when switch flipped on?
My instructor put in the notes a picture of a loop without an inductor -
just a battery with voltage $\epsilon$, a switch, and resistor with resistance $R$. He explains that as soon as the switch is ...
- 1,177
1
vote
1
answer
784
views
Non-conservative Electric Field
I was watching this video from Walter Lewin and while watching these two videos, I noticed there is a "contradiction" in what he is doing. All links direct you exactly to where he begins, so you don't ...
- 937
1
vote
1
answer
58
views
Does the presence of a disconnected coil nearby affect the self-inductance of a coil under test?
Picture two coils in close proximity. They have the same dimensions and are located co-axially, with a small gap between then (like Helmholtz coils, but much closer together than in the standard ...
- 111