How will electrons flow in a very long conductor?

AI Thread Summary
In a discussion about electron flow in an infinitely long conductor connected to two charged spheres, it is established that while the electric fields at points A and B may be zero, an electric potential difference is necessary for current to flow. The spheres, being conductors, allow electrons to move; electrons will flow from the positive sphere to neutralize its charge while excess electrons from the negative sphere will enter the conductor. However, the flow of electrons is directly proportional to the electric field strength, which diminishes as current flows, leading to a reduction in charge difference between the spheres. This results in a quick balancing of charges that ultimately stops the current. Therefore, while initial electron movement occurs, it is short-lived due to the rapid equalization of charge.
erocored
Messages
30
Reaction score
7
I have two charged spheres connected to different ends of an infinitely long conductor. The first sphere has positive charge, another sphere has negative charge. Suppose that the electric field of the first sphere at point A is zero, and the electric field of the second sphere is zero at point B. Will be any current in this conductor?
 
Physics news on Phys.org
An infinitely long conductor has no ends.
 
PeroK said:
An infinitely long conductor has no ends.
I mean two spheres are so distant that their electric fields do not interact
 
erocored said:
I mean two spheres are so distant that their electric fields do not interact
You still must have an electric potential difference. And interaction between the charges in the conductor and the spheres at either end.
 
PeroK said:
You still must have an electric potential difference.
Then what will move electrons through the segment AB?
 
erocored said:
Then what will move electrons through the segment AB?
The electric field is never zero for either sphere.

Are the spheres insulators or conductors themselves?
 
PeroK said:
The electric field is never zero for either sphere.

Are the spheres insulators or conductors themselves?
spheres are conductors. Is this almost zero electric field enough to move electrons?
 
erocored said:
spheres are conductors. Is this almost zero electric field enough to move electrons?
Electrons at one end of the conductor will be drained off to neutralise the positive charge; and the excess electrons on the negative sphere will drain into the conductor. Just as you should expect.
 
  • Like
Likes vanhees71 and erocored
erocored said:
spheres are conductors. Is this almost zero electric field enough to move electrons?
The flow of electrons is proportional to the strength of the electric field across the conductor. There is no deadband or hysteresis.

The tricky thing about you scenario is that as soon as some current flows, the charge difference between the spheres will reduce and decrease the electric field. The charges will quickly balance and the current will stop flowing.
 
  • Like
Likes vanhees71 and erocored
Back
Top