What are the fields produced around a current carrying conductor?

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Discussion Overview

The discussion revolves around the fields produced around a current-carrying conductor, focusing on the existence of electric and magnetic fields. Participants explore theoretical aspects, implications of Ohm's law, and the behavior of superconductors versus ordinary conductors.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants propose that a current-carrying conductor, despite having no net charge, can still produce an electric field due to the movement of electrons.
  • Others argue that Gauss' Law indicates that while there may be an electric field, the total electric flux through a closed surface is zero if there is no net charge inside.
  • A conductor with finite resistivity will have both an electric field and a magnetic field, while a superconductor carrying a steady current will only have a magnetic field.
  • Some participants question the need for sources to support claims about superconductors and electric fields, suggesting that the concepts are basic and well-established.
  • There is a discussion about the relationship between stationary and time-dependent currents, with some noting that stationary currents produce stationary magnetic fields, while time-dependent currents induce electric fields.
  • Participants correct each other on the application of Ohm's law and the symbols used for conductivity and resistivity, indicating a shared understanding of the underlying principles.
  • One participant raises a point about the contradiction in referring to "stationary current," suggesting that current, by definition, implies flow.

Areas of Agreement / Disagreement

Participants express differing views on the existence and nature of electric and magnetic fields around current-carrying conductors, with no consensus reached on several points, particularly regarding superconductors and the implications of Ohm's law.

Contextual Notes

Some statements rely on assumptions about the definitions of current, electric fields, and magnetic fields, which may not be universally agreed upon. The discussion also touches on the nuances of stationary versus time-dependent currents, which remain unresolved.

  • #31
The E is the field within the superconductor, not just at the ends, but at any point within.

For the fields outside the conductor you would need to solve Maxwell's equations. I believe that there would also be no E-field outside of a superconducting wire, unless imposed externally, but I cannot justify that at the moment.
 
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  • #32
DaleSpam said:
For the fields outside the conductor you would need to solve Maxwell's equations. I believe that there would also be no E-field outside of a superconducting wire, unless imposed externally, but I cannot justify that at the moment.

Anyway, thank you for the info on the fields within the current carrying conductors.

I look forward if anyone wants to reply for the actual question. I quote it once again:

Godparicle said:
If we consider a current carrying conductor, every instant an electron enters the conductor, another electron will be leaving the conductor. Thus, the current carrying conductor will not be charged (i.e, it would not have any net positive or negative charge). Remember dipole has zero net charge, but it does have electric field around it. So, if net charge is zero, it doesn't mean there is no electric field.

It is important to notice that, if we assume only electrons to be moving, and kernels (positive nuclei) to be static, magnetic field will be produced only due to electrons.

Does it mean that electric field and magnetic field exists around the current carrying conductor?
Or
Does it mean that only magnetic field exists around the current carrying conductor?

The question is simple, but I have found varied answers until now.
 
  • #35
Yes, I was intrigued by some of the results, particularly the Poynting vector. It seems that in a very reasonable sense power doesn't flow through a wire.
 

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