How will electrons flow in a very long conductor?

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Discussion Overview

The discussion revolves around the behavior of electrons in an infinitely long conductor connected to two charged spheres, one positively charged and the other negatively charged. Participants explore the implications of electric fields, potential differences, and the conditions necessary for current flow in this theoretical setup.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions whether there will be any current in the conductor given that the electric fields of the charged spheres are zero at specific points.
  • Several participants clarify that an infinitely long conductor has no ends, which raises questions about the nature of electric fields in this context.
  • It is suggested that the spheres are so distant that their electric fields do not interact, yet another participant emphasizes the necessity of an electric potential difference for current to flow.
  • Participants discuss the role of electric fields and whether a near-zero electric field can still facilitate electron movement through the conductor.
  • One participant proposes that electrons will flow to neutralize the positive charge on one sphere and that excess electrons will drain from the negative sphere into the conductor.
  • Another participant notes that the flow of electrons is proportional to the strength of the electric field and mentions that current will stop flowing once the charge difference between the spheres reduces.

Areas of Agreement / Disagreement

Participants express differing views on whether current can flow in the conductor under the given conditions, with no consensus reached regarding the implications of electric fields and potential differences.

Contextual Notes

The discussion includes assumptions about the distances between the spheres and the nature of the electric fields involved. The implications of charge balance and the dynamics of current flow remain unresolved.

erocored
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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?
 
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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.
 
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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.
 
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