All Questions
47
questions
1
vote
1
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40
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Confusion about EM waves in a conductor, AC in wires, and skin effect
I am trying to get my head around these different points:
From Maxwell's equations we find that an electromagnetic wave in a conductor decays in amplitude with a characteristic length of about 1 cm in ...
- 197
0
votes
0
answers
27
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Can you measure different currents at different contact points for a volume of material made of two different metals with different conductivities?
My question is about the variation of conductivity in a volume of material and its effect on measured current. A volume is comprised of two metals joined symmetrically in a cuboid shape as in the ...
2
votes
4
answers
1k
views
Why is current density in a conductor of uniform cross sectional area constant at all points?
According to what I was taught, if current was dispersed “uniformly,” current density would remain constant.
So, in a conductor, the 'current density should be the same at all points.' But, given that ...
- 444
0
votes
1
answer
150
views
Would a grounded copper heat sink located near a room's ceiling be an effective way to reduce a room's temperature?
I am thinking about a cheap but effective way to reduce the temperature of my bedroom in my apartment during hot summer nights. I live in an old apartment building and the air conditioner located in ...
- 478
0
votes
1
answer
72
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Running electrolysis on inside surface of a tube
I use electrolysis for rust removal and electroplating. I notice that when one of the electrodes is a closed tube or has other topological holes with a sufficiently large height:diameter ratio, the ...
- 1,004
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 ...
1
vote
2
answers
758
views
What force moves electrons through a conductor that is rotating in a magnetic field [closed]
Is it the magnetic force ( F= qv +B ) or the electromagnetic force (F= q(E+vxB) that acts on the electrons of a conductor that is moving in a magnetic field?
Thanks.
user232620
0
votes
1
answer
71
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How is electric current possible if no electric field exists inside a conductor?
How is electric current possible if no electric field exists inside a conductor?
Since no electric field exists inside a conductor. How is electric current possible as $$v_d=\frac{(eE)t}{2m},\;\;{E=0}...
- 1
3
votes
1
answer
690
views
Does the shape of a wire affect the electric current in it in any way?
Say we have a straight wire connected across two terminals carrying electricity between them. If everything is kept the same (voltage across the two terminals, resistance of the wire, etc.) will there ...
- 195
5
votes
4
answers
977
views
If an electron is repelled by another electron how is it that we get an electric current?
As we know that an electric current is a flow of electric charge in a circuit, and in electric circuits, the charge carriers are often electrons moving through a wire.
Now, since we know that like ...
0
votes
1
answer
62
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GENERATION OF CURRENT DUE TO ELECTRON FLOW
Why do flow of electrons generate current? whenever an electrons flows through a wire it generates electricity why does it actually happen?
- 31
3
votes
3
answers
233
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What do $\ell$ and $A$ precisely mean in the formula for electrical resistance?
The formula for resistance is
$$R=\rho\frac{\ell}{A}$$
Generally in most of the textbooks it simply written that $\ell$ is the length of the conductor and $A$ is it’s cross-sectional area. But my ...
- 155
1
vote
1
answer
93
views
Does the electron in wire too move because of voltage difference?
When we talk about electricity through a circuit because of a battery it is said that the electrons from negative terminal travel to positive terminal of the battery.
I can't help but imagine about ...
- 300
0
votes
0
answers
611
views
Current equation $I=nqA\vec{v}_d$
I was reading from several introductory E&M materials, and they all state that $$I=neA\vec{v}_d$$where $n$ is number of free charge carriers, $e$ is the elementary charge of electron, $A$ is cross-...
0
votes
1
answer
118
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When AC electricity is generated, how does the current flow? [duplicate]
I have read multiple different versions of how AC current flows in our power lines. How does the current flow? Is the energy just photonics waves passing through electrons that vibrate or are ...
- 1