How can the electric field inside a conductor be zero?

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Discussion Overview

The discussion revolves around the question of whether there can be an electric field inside a conductor, particularly in the context of a charged hollow conductor and the effects of introducing a charge within it. Participants explore theoretical and practical implications of electric fields in conductors, addressing concepts from electrostatics and dynamics.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants assert that in a charged conductor, the electric field inside should be zero under static conditions, while others argue that introducing a charge (like an alpha particle) can create an electric field due to charge redistribution on the conductor's surface.
  • It is proposed that if the charge on the surface of a hollow conductor is not uniformly distributed, an electric field can exist inside the conductor.
  • Some participants suggest that adding a charge inside the hollow conductor disrupts the surface charge distribution, leading to the formation of an electric field.
  • There is a distinction made between static and dynamic scenarios, with some arguing that the presence of a moving charge (like an alpha particle) complicates the situation.
  • Participants discuss the concept of electrostatics, noting that the textbook statement about zero electric field applies strictly to electrostatic conditions.
  • One participant mentions that realistic conductors can have a small electric field inside due to resistance, contrasting with the idealized notion of perfect conductors.
  • Clarifications are made regarding the behavior of charges and fields in non-conducting versus conducting materials within the context of the hollow conductor.

Areas of Agreement / Disagreement

Participants express differing views on the existence of electric fields inside conductors, particularly when charges are introduced. While some agree on the conditions under which electric fields can exist, others maintain that the traditional understanding of zero electric field in electrostatic conditions holds true. The discussion remains unresolved with multiple competing views present.

Contextual Notes

Participants highlight the importance of distinguishing between static and dynamic situations, as well as the implications of charge distribution on electric fields. There is also mention of the limitations of idealized models in explaining real-world behavior of conductors.

  • #31
ycheng18 said:
"Now there is a field within the sphere due to the surface charge"

So does this mean there can be electric fields inside a hollow charged conductor?
If you put a charge inside the shell then certainly an E field exists inside the shell. E.g. put it at the center, the E field inside the shell is kq/r^2 directed everywhere away from the center. But a radioactive decay means there are +2q and -2q charges inside the shell, doesn't it? So I assume you imply that the electrons are shot away outside the shell?
 
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  • #32
ycheng18 said:
"Now there is a field within the sphere due to the surface charge"

So does this mean there can be electric fields inside a hollow charged conductor?
Already here you have changed the situation. You started with a solid sphere, now it's a hollow sphere.

Bottom line: if it's solid there is no E field inside it; all the charge gets distributed evenly about its surface regardless of how much extra charge you stuff inside it. (if it's a poor conductor just give it a bit of extra time).

If it's a hollow sphere (a shell) you can put a charge inside the shell and then yes there will be a finite E field inside.

The whole discussion from this post on seems to flounder on the confusion between a solid and a hollow sphere ...
 
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  • #33
ycheng18 said:
Well, we've just started to learn electrical fields 2 weeks ago (I am in 2nd year IB HL Physics). I don't really know what a flux is either. I was just confused about how it is possible that the textbook/teacher says "there is no electric field inside a hollow sphere". But I guess this is a topic that is too advanced for me currently, I might revisit this when I learn about more advanced stuff (maybe later in the year or in college). But thank you for answering my question.

What your instructor was saying is basically what Newton concluded early in his work on gravitation - that a radially symmetric (mass) density field has the effect of being as if it were a point mass at the center, and that the gravity field inside any particular radial distance due to the mass outside of that radial distance is zero. This applies to any inverse-square law force, which of course static electricity behaves as.
 

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