All Questions
34
questions
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
4
votes
2
answers
537
views
What does 'Oppose a Change in Current' really mean from Lenz Law?
We all know what Lenz Law is, but I have a bit of trouble conceptualizing the phrase above. Does 'Oppose a Change in Current' means it will take more time for the current to increase to its maximum ...
user215726
3
votes
2
answers
10k
views
Self-induction in a circular coil
There's a formula for self inductance: $$ L=\frac{n\Phi}{i}$$ where n is the number of loops.
But the book also says self inductance is directly proportional to $ n^2 $
I totally agree with the ...
- 366
2
votes
2
answers
573
views
Does an inductor stretch or compress when a current is passed through it?
If an inductor is given to you and it is connected across a battery without any resistance in the circuit,then will the inductor stretch,compress or remain the same length?
2
votes
3
answers
534
views
Why can't the current in a solenoid be changed rapidly?
Why can't the current in a solenoid be changed instananeously? My reasoning is since the current in a solenoid is given by a integral:
$$I(t) = \frac{1}{L} \int_{t_0} ^{t_f} V_Ldt$$
then if $t_f = t_i ...
- 548
2
votes
4
answers
250
views
Inductor connected to an AC source
Consider an inductor connected to an AC source, $V=V_0\sin\omega t$.
Let the the switch in the circuit be closed at $t=0$. Then by Kirchoff's voltage law,
$$
V-L\frac{dI}{dt}=0
$$
where $I$ is the ...
- 23
1
vote
4
answers
4k
views
Why isn't there any current in the primary if secondary circuit is opened in a transformer?
Consider an ideal transformer, with no load/resistor attached on the secondary (ppen circuit). It is said that the primary would act as if it is an open circuit too, thus no current flows through the ...
user215726
1
vote
2
answers
515
views
What is the amplitude of current in LC oscillations
Since there is no resistance in an LC circuit (not attached to an AC source), what's stopping the current from rising to infinite. And if resistance is provided by the inductor by self induction, then ...
- 105
1
vote
3
answers
442
views
How can it be justified that the phase difference between voltage and current for inductor is $\pi/2?$
The inductor is an ideal one, the phase difference is with respect to current, and the voltage varies by the law $V=V_Lsin(\omega t).$
One can prove that the current function will come out to be $I=...
- 480
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
1
answer
220
views
Current and Magnetic Poles of a Solenoid (Diagram) & Right Hand Thumb Rule
Well, my doubt's pretty elementary.
Firstly I wanted to confirm whether both the cases, as illustrated in the picture, are correct. I've darkened the part of each coil that faces us. Using the clock-...
- 72
1
vote
1
answer
77
views
Inductors in AC circuit
We know that the current varries in an a.c. circuit if we connect an inductor to the circuit when the current is maximum the inductor oppose the current and tries to decrease the current and when ...
- 31
1
vote
2
answers
3k
views
Why is the induced current greatest when a generator's loop is in the direction of the magnetic field?
This is a topic that has been confusing me for a while now.
take this picture for instance
We know that a current is induced when a conducting loop experiences a change in magnetic flux. So I ...
- 193
1
vote
1
answer
73
views
Mathematical expression for self-inductance constant $L$?
Is there a mathematical expression for what the value of $L$ (self-inductance constant) is for a given geometry? I've tried to come up with something, but I don't know if it's right or not...
$$\phi_B=...
- 187
1
vote
1
answer
214
views
What does an induced emf do to a loop of varying current?
I know that the magnetic flux through a loop in space is proportional to the current such that $\Phi=LI$. Therefore a change in magnetic flux will produce an emf, so $\mathscr{E}=-L\dfrac{dI}{dt}$. ...
- 518