Confusion with the direction of E-fields near conductors

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Discussion Overview

The discussion revolves around the behavior of electric fields (E-fields) near conductors, particularly focusing on the directionality of these fields and the implications of charge distribution on the surface of conductors. Participants explore theoretical concepts related to electric fields, charge movement, and the interface between different media.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants suggest that if the electric field is not perpendicular to the surface of a conductor, charges would move along the surface, leading to uneven charge density.
  • There is a discussion about the assumption that the electric field magnitude is constant over a small area, which may not hold true due to varying charge densities.
  • One participant notes that the tangential component of the electric field is preserved at the interface between two media, implying that if the field inside the conductor is zero, the tangential component outside must also be considered.
  • Another participant questions the implications of having a tangential electric field component at the surface of a conductor, suggesting it would cause electrons to move until equilibrium is reached.
  • Some participants express confusion about the concept of an interface between two media and its relevance to the electric field behavior at the surface of conductors.
  • There is a mention of the effect of surface curvature on charge distribution, indicating that uneven surfaces can lead to non-uniform charge densities.
  • Mathematical reasoning is introduced regarding the relationship between electric fields across an interface, with references to integrals and boundary conditions.

Areas of Agreement / Disagreement

Participants express varying interpretations of the behavior of electric fields at the surface of conductors, with no clear consensus on the implications of tangential components or the effects of charge distribution. The discussion remains unresolved with multiple competing views.

Contextual Notes

Some assumptions about the uniformity of charge distribution and the behavior of electric fields near conductors are not fully explored, leading to potential gaps in understanding the implications of surface curvature and external fields.

  • #31
rudransh verma said:
@DaveE To summarise I will say there is a isolated conductor which has zero E inside and outside. Now it’s charged. For a brief moment there will be a net internal electric field due to all these charges but that net field will soon disappear because these charges will soon redistribute itself in such a way that the net field on each charge due to all charges is zero. Field at every point become zero. Now the charges are at the surface making perpendicular field to the surface. Why? Its true that the outside tangential field will have an effect inside tangentially. But that doesn’t mean outside field is perpendicular. The field can well be at an angle and there would be an internal tangential field. Why are we saying because the internal field is zero! Of course It’s will be zero . All the charges are now on surface. Real reason is that the charges don’t move on the surface. That’s why the field lines are perpendicular to the surface.
I guess it was experimentally seen that charges don’t move on the surface. They become static. That is why we say fields are perpendicular.

@ergospherical You say inside field is zero. Tangential field both inside and thus outside is zero. Field is so perpendicular. But isn’t it possible that there is no field inside but the field due to surface charge is not perpendicular and have a tangential component along the surface.
No. I'm not sure I have anything to add that hasn't previously been said.
 
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  • #32
DaveE said:
No
So you are saying there will be a tangential field inside in that case. Ok then let there be. Are you saying field inside has been found zero when measured in case of charges on the surface.
 
Last edited:
  • #33
rudransh verma said:
So you are saying there will be a tangential field inside in that case. Ok then let there be. Are you saying field inside has been found zero when measured in case of charges on the surface.
No. I didn't say that.
 
  • #34
DaveE said:
No. I didn't say that.
Please explain!
 
  • #35
As I said before, I think I did previously explain what I can. Maybe more reading of answers than asking redundant questions would help you? I'm sorry if you don't understand what I was saying, but I don't know how to say it more clearly.
I think I'm done here.
 
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  • #36
rudransh verma said:
What does that mean? I didn’t catch you. Also Please complete your sentence.
Change in e sub r.
This changes the ratio between B field and E field intensity in the location.
tangential current exists to carry this E field component.
 
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