Question about flow of electrons along wire.

AI Thread Summary
Electrons flow through a wire from the source to the receiver, but they cannot be retained in the wire once the source and receiver are disconnected. In copper, there are approximately 1.38*10^22 conduction electrons per gram, regardless of external conditions. Unlike water in a hose, which flows rapidly when a tap is opened, electricity behaves differently; the wire is already filled with electrons. When voltage is applied, electrons begin to move, but their actual speed is quite slow, typically only a few centimeters per second. The effectiveness of electricity lies in the vast number of electrons rather than their speed.
pghazanfari
Messages
4
Reaction score
0
I know that electrons flow across the wire from the source to the receiver, but would it be possible to keep these electrons on the wire after disconnecting the source and receiver?
 
Physics news on Phys.org
pghazanfari said:
I know that electrons flow across the wire from the source to the receiver, but would it be possible to keep these electrons on the wire after disconnecting the source and receiver?

There are always about 1.38*10^22 conduction electrons (1 for each copper atom) in every gram of copper whatever you do with it.
 
I know that electrons flow across the wire from the source to the receiver

When you connect a garden hose to a tap an turn it on water starts flowing down the pipe rapidly from source to receiver. This is NOT how it works for electricity.

For electricity it's better to think of the hose as already full of water (wire already full of electrons). Then when the tap is opened water comes out at the receiver almost immediately.

Although electrons start coming out soon after a voltage is applied they actually travel very slowly down the wire. If I remember correctly typical speeds are only a few cm per second. What makes electricity so powerful is the sheer number of them not their velocity.
 
Thread 'Motional EMF in Faraday disc, co-rotating magnet axial mean flux'
So here is the motional EMF formula. Now I understand the standard Faraday paradox that an axis symmetric field source (like a speaker motor ring magnet) has a magnetic field that is frame invariant under rotation around axis of symmetry. The field is static whether you rotate the magnet or not. So far so good. What puzzles me is this , there is a term average magnetic flux or "azimuthal mean" , this term describes the average magnetic field through the area swept by the rotating Faraday...
It may be shown from the equations of electromagnetism, by James Clerk Maxwell in the 1860’s, that the speed of light in the vacuum of free space is related to electric permittivity (ϵ) and magnetic permeability (μ) by the equation: c=1/√( μ ϵ ) . This value is a constant for the vacuum of free space and is independent of the motion of the observer. It was this fact, in part, that led Albert Einstein to Special Relativity.

Similar threads

Replies
4
Views
2K
Replies
5
Views
2K
Replies
4
Views
3K
Replies
36
Views
6K
Replies
14
Views
4K
Replies
7
Views
7K
Replies
29
Views
17K
Back
Top