30
votes
Accepted
How will the current flow in the figure drawn below?
An approximate numerically calculated figure is attached.
The figure is a two-dimensional result.
Although 3D calculations is possible, the figure is easier to see in 2D.
$\phi$ is potential in volts.
...
- 496
6
votes
Accepted
Example of information travelling faster than the speed of light?
Therefore, we can use the law of Biot-Savart
No, you cannot use the Biot Savart law in this situation. The Biot Savart law is derived from the magnetostatic assumption. That is, the assumption that $...
- 65.8k
6
votes
Accepted
How to calculate the total resistance of the 5-cell (4 dimensional pyramid)?
In the article:
Severino V. Gervacio, "Resistance distance in complete $n$-partite graphs", Disc. App. Math. 203, pp. 53–61
the author cites the surprising and elegant result (see refs. [3,...
- 38.3k
6
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How does current flow in a purely inductive circuit if the net voltage is zero?
How does current flow in a purely inductive circuit if the net voltage is zero?
The problem in this question is that it is based on a completely wrong assumption. This concept of “net voltage” isn’t ...
- 65.8k
5
votes
How will the current flow in the figure drawn below?
Yes. There won't be any noticeable amount current at the ends of the rod because the electric field formed inside the conductor will be restricted so the electrons will dominantly experience the force ...
- 672
4
votes
How does current flow in a purely inductive circuit if the net voltage is zero?
When the source voltage is suddenly made zero then the current will be decreasing at some rate and if an ideal inductor is present in a circuit then that decaying current will cause the magnetic flux ...
- 672
4
votes
Accepted
Quantum Computing is not Analog Computing. Really?
Quantum computers are like classical analog computers in that they have a continuous state space, and are like classical digital computers in that they have a discrete output space.
Anything beyond ...
- 17.5k
3
votes
Quantum Computing is not Analog Computing. Really?
Quantum computing is a form of digital not analog computing. I will explain why.
First, let's note that the fact that the physical state space is continuous is not the relevant fact. For the physical ...
- 47.1k
3
votes
Why are computers much smaller than they are fast?
For a wire, a vast number of electrons are present. They barely move. Each electron only needs to move slightly to play its part in guiding the electromagnetic field along the wire. The signal ...
- 4,121
3
votes
Why does an electric field "concentrate" along a wire?
This is indeed something that seems rather mysterious at first. It is well known in the literature, but is often not discussed in a typical EE curriculum. It seems like the physics classes don’t think ...
- 65.8k
3
votes
Does current flow inside a battery?
Yes. When a battery is operating normally then current flows inside the battery from the negative terminal to the positive terminal.
- 65.8k
2
votes
Accepted
Why is it safe to touch a Van Der Graaf Generator?
Why is it safe to touch a Van Der Graaf Generator?
If by "safe" you mean not causing ventricular fibrillation, then it's because the energy of the capacitive discharge is not sufficient to ...
- 56.1k
2
votes
Accepted
Cant understand why $C_1$ and $C_1$ are in parallel?
The two C1's are not in series, for exactly the reason you say.
However, because C1 is equal to C1 and C2 is equal to C2, we can show by symmetry that, assuming we start with all capacitors discharged,...
- 23k
2
votes
How does current flow in a purely inductive circuit if the net voltage is zero?
If we're talking about a purely inductive circuit, the induced emf is equal and opposite to applied emf. Isn't it just like two identical batteries in opposition?
If that's the case, how does the ...
- 28.4k
2
votes
Why are computers much smaller than they are fast?
Someone else with more knowledge can correct me, but I think it might have to due with either the capacitive effect or the field effect in circuits. 1) electrical components often have some capacitive ...
- 41
2
votes
Induced e.m.f and induced current in a Electro Magnet during Electro Magnetic Induction
1 My question is, . . . . . . , the induced current will be developed in the 1st wound,and it will reduce the actual current heavily, so when the current will reach the 2nd wound, . . . . . . so ...
- 77.9k
2
votes
What happens to a non-conductive material in a circuit?
An electric fence works by having an open circuit in normal conditions, and then only having a closed circuit when an animal touches the fence. So the end of the wire is not particularly problematic ...
- 65.8k
1
vote
Electricity Paradox
In a static situation, zero resistance implies no potential difference. The current keeps flowing through the branch without resistance even after the source for initiate the current is not more ...
- 12.3k
1
vote
Why dose current only take the path of zero resistance in a parallel circuit?
[...] What stops the the current from flowing thought the resistor?
Well, the resistance stops it. Every charge that reaches the junction will move in the direction of least resistance. They will ...
- 46.6k
1
vote
Why dose current only take the path of zero resistance in a parallel circuit?
Suppose there is 1 A flowing through the zero-resistance wire.
What then is the voltage across the wire? From Ohm's law we know the voltage across it is 0 V.
Since the other resistor is in parallel, ...
- 23k
1
vote
What is the correct definition of EMF in a circuit?
What is the correct definition of emf in a circuit?
Neither of the equations you wrote is the definition that Griffiths provided for EMF. His definition of EMF is in Eq. 7.9 of the reference you ...
- 7,614
1
vote
The misconceived difference between the electrostatic and electric force
(It's a good idea to provide specific references, rather than some vague "source".)
The electric force is $\vec F_{elec}=q\vec E$.
Such a force can be called "electrostatic"
the ...
- 8,677
1
vote
Induced emf by a single wound coil
The induced emf depends on the rate 0f change of current not the value of the current itself and it can never "win" in the sense of stopping the current completely because it id does then ...
- 77.9k
1
vote
Why are computers much smaller than they are fast?
In CMOS every input to a transistor or gate is driven by a precious CMOS output.
So in all cases you end up with a rather high source impedance R (say 10 kOhm) driving a capacitive input C (say 1 fF).
...
- 730
1
vote
Accepted
Showing that its always possible to convert the circuit into the below equivalent form
Well at the end of the day if electricity flow is coming in let's say by A and going out by B and C, you will have some proportion of how much goes through B and how much through C and that will give ...
- 551
1
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How does current flow in a purely inductive circuit if the net voltage is zero?
There is a perfect mechanical analogy. If we push an idle car in a flat ground, we feel a force $$F = -m\frac{dv}{dt}$$ where $m$ is the mass of the car and $v$ its velocity. Of course, at $t=0$, the ...
- 12.3k
1
vote
Find the EMF of the source in the circuit
The question doesn't tell you WHERE the work is to be done. To get the answer given for the emf, you have to assume that the 1000 J is the total work done in the circuit, that is the sum of the work ...
- 28.1k
1
vote
Accepted
Why don't we know the electric potential at any point in a circuit, only the difference in the electric potential (voltage)?
In loop analysis where we apply Kirchhoff's voltage law (the algebraic sum of the potential differences around a loop equals zero) it is only necessary to consider potential differences.
In doing node ...
- 56.1k
1
vote
Accepted
How does a capacitor discharge through another capacitor and resistor?
The resistance determines how fast the charge will transfer from one capacitor to the the othr. The final state is determined by the equality of the potential diference across the two capacitors. The ...
- 6,568
1
vote
Accepted
What would be the shape of the magnetic field around a current carrying wire made up from iron?
With the relative permeability $μ_{r}$ of copper at ~0.999 (diamagnetic) and aluminum as well as air at ~1 and for pure iron (99.8%) about ~5000 (https://www.engineeringtoolbox.com/permeability-d_1923....
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Only top scored, non community-wiki answers of a minimum length are eligible