Electric field at the surface of a conductor

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Homework Help Overview

The discussion revolves around the behavior of electric fields at the surface of conductors and insulators, particularly in static situations. Participants are examining the implications of electric field components parallel to the surface and how they relate to the mobility of charges in different materials.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the validity of a statement regarding electric fields at the surface of conductors versus insulators, questioning the implications of charge mobility and static conditions.

Discussion Status

There is an ongoing examination of the original statement's applicability to insulators, with some participants asserting that the argument does not hold for insulators due to the immobility of charges. Multiple interpretations of the conditions under which the statement applies are being explored.

Contextual Notes

Participants are considering the definitions of static situations and the behavior of charges in conductors versus insulators, noting that the original statement may not apply uniformly across different materials.

jakeham
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Homework Statement


Put in plain words: "In a static situation, the electric field at the surface of a conductor can have no component parallel to the surface, because this would violate the condition that the charges on the surface are at rest."
Would this same statement be a valid one for tha electric field at the surface of an insulator?


Homework Equations


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The Attempt at a Solution


I can't understand the sentence, and can't figure out if it's valid for an insulator.
 
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The charges in a conductor are mobile. If there is a parallel component of the electric field at the surface then it will cause the surface charges to move (hence not 'static'). The charges in an insulator are not mobile. So the argument doesn't hold.
 
In a STATIC situation, the charges ARE at rest. The statement holds
 
chaoseverlasting said:
In a STATIC situation, the charges ARE at rest. The statement holds

The 'statement' is that there is no E field component parallel to the surface of the body. In the insulating case the charges won't move even if there is an E field. Hence there CAN be a E field in the static case. Hence the statement does NOT hold.
 

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