All Questions
26
questions
0
votes
1
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2k
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Magnetic field generated pointing upwards, what direction is induced current?
In this Crash Course video, from 5:57 to 6:15, I think the directions are mixed up, but I could be wrong. She says that when moving the magnet into the loop, the generated magnetic field is pointing ...
- 1,177
0
votes
2
answers
889
views
Why can't mutual inductance create perpetual electricity?
Consider the following image.
When the battery is connected then current starts flowing through the primary cicuit and magnetic flux changes through the coil, this causes electricity to be induced in ...
- 378
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
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
1
vote
3
answers
1k
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Current through two inductors after a long time
I'm having trouble with visualizing the following problem, which is asking me for the final, steady current in both inductors $L_{1}$ and $L_{2}$. I was thinking that after a long time, essentially ...
- 111
1
vote
1
answer
1k
views
Energy in a Solenoid?
Consider a circuit consisting of a battery, a resistor and a solenoid inductor. Then, the emf $\mathcal{E}$, is defined as:
$$\mathcal{E} = L\frac{di}{dt} + iR$$
Multiplying both sides by $i$ gives:
$$...
- 2,009
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
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
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
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
2
votes
1
answer
408
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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