All Questions
47
questions
45
votes
5
answers
61k
views
Speed of light vs speed of electricity
If I arranged an experiment where light raced electricity what would be the results? Let's say a red laser is fired at the same time a switch is closed that applies 110 volts to a 12 gauge loop of ...
- 4,711
18
votes
5
answers
12k
views
How does a wire carry alternating current?
Consider a simple network of a bulb whose two terminals are connected to two wires with open ends A and B respectively
A o--------💡--------o B
Now if a DC ...
- 510
15
votes
3
answers
7k
views
Tree vs lightning rod: why does one burn and the other not?
I have this simple question, but I cannot find the answer.
I saw this video about a plane getting hit by lightning. In it, Captain Joe explains why people do not get electrocuted. This has a simple ...
- 314
8
votes
9
answers
6k
views
Why does electricity need wires to flow?
If you drop a really heavy ball the ball's gravitational potential energy will turn into kinetic energy.
If you place the same ball in the pool, the ball will still fall. A lot of kinetic energy will ...
- 2,009
5
votes
4
answers
987
views
If an electron is repelled by another electron how is it that we get an electric current?
As we know that an electric current is a flow of electric charge in a circuit, and in electric circuits, the charge carriers are often electrons moving through a wire.
Now, since we know that like ...
5
votes
2
answers
695
views
Why do electrons follow the conductors shape?
I'm stuck thinking about this situation. I imagine that there are two oppositely charged objects at short distance $r$, put inside an insulator (Can I say air?). They generate a net elctric field, ...
4
votes
6
answers
2k
views
Electric current definition
I'm trying to understand electric current. Some resources say that it is the flow of charge, and other resources say that it is the quantity of charge that passes through a cross-sectional area over a ...
3
votes
3
answers
2k
views
When current passes through a wire, does it only travel through the outer surface?
In electrostatics we are taught that the field inside a conductor is always zero. So when current passes through a wire, the electricity only passes through the surface of the conductor.
In magnetism, ...
- 353
3
votes
3
answers
235
views
What do $\ell$ and $A$ precisely mean in the formula for electrical resistance?
The formula for resistance is
$$R=\rho\frac{\ell}{A}$$
Generally in most of the textbooks it simply written that $\ell$ is the length of the conductor and $A$ is it’s cross-sectional area. But my ...
- 155
3
votes
2
answers
1k
views
How is the speed of electricity determined?
Before I am told this is a duplicate, I'd like to be specific here. I have searched online for an answer regarding the speed of electricity in general and haven't found what I'm looking for. Even in ...
3
votes
1
answer
101
views
Direction of AC current in a very long wire [closed]
Suppose an external wire of length 10^8 meter (very long indeed) is connected in between the slip rings of an AC generator externally. Taking the speed of current propagation to be ~10^7 m/s, then it ...
user63923
3
votes
1
answer
698
views
Does the shape of a wire affect the electric current in it in any way?
Say we have a straight wire connected across two terminals carrying electricity between them. If everything is kept the same (voltage across the two terminals, resistance of the wire, etc.) will there ...
- 195
3
votes
4
answers
15k
views
How does the drift velocity of electrons in a conductor depend on the temperature?
How does the drift velocity of electrons in a conductor depend on the temperature?
I have two contradicting views for this.
First, we can say that increasing the temperature of the conductor will ...
- 1,582
3
votes
1
answer
525
views
How do electrons move at an atomic level? [duplicate]
This was meant to be a sub question in the comments of my last question but I think it is big enough to have its own post.
I know that electrons move because of the potential difference across the ...
- 705
2
votes
2
answers
2k
views
Is there no electric field inside a conductor?
I came across this statement while studying electric currents and I am confused:
"There is no electric field inside a conductor. Hence no current can flow through it".
Is there a fallacy in this ...
- 447