Why Electric Fields are perpendicular

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Homework Help Overview

The discussion revolves around the relationship between electric fields and equipotential surfaces, particularly in the context of conductors. Participants explore the implications of electric fields being perpendicular to equipotential surfaces and how this applies to the surface of a conductor.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants attempt to understand the behavior of electric fields in conductors, questioning how the absence of charge within a conductor affects electric field lines. They also explore the implications of measuring voltage on a conductive surface and what that indicates about the electric field.

Discussion Status

Some participants have provided insights regarding the nature of equipotential surfaces and the orientation of electric fields. There is an ongoing exploration of the concepts, with no explicit consensus reached, but productive direction is evident as participants connect ideas about potential difference and electric field orientation.

Contextual Notes

Participants are discussing the scenario of measuring voltage on a conductive surface, considering the implications of little or no current flowing in the conductor. The discussion includes assumptions about the behavior of electric fields in relation to equipotential surfaces.

KatieD
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Homework Statement


If electric fields are perpendicular to the equipotential surface, what is the orientation of the field on the surface of a conductor (like metal)? Why is this so?


Homework Equations



E= ∆V/d

The Attempt at a Solution



I know that there is no charge within a conductor and it moves to the edges. I am confused with how this affects the electric field lines. I also know that electric field lines point out if a charge is positive and in if a charge is negative.

I am just confused with electric fields when there is a conductor.

Thanks :)
Katie
 
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KatieD said:

Homework Statement


If electric fields are perpendicular to the equipotential surface, what is the orientation of the field on the surface of a conductor (like metal)? Why is this so?


Homework Equations



E= ∆V/d

The Attempt at a Solution



I know that there is no charge within a conductor and it moves to the edges. I am confused with how this affects the electric field lines. I also know that electric field lines point out if a charge is positive and in if a charge is negative.

I am just confused with electric fields when there is a conductor.

Thanks :)
Katie

If you use a DVM to measure the voltage difference between two points on a conductive surface, what voltage do you think you will measure (assuming little or no current is flowing in the conductor)? Does that help?
 
You won't measure any voltage, does this mean that the electrical field would be zero?
 
KatieD said:
You won't measure any voltage, does this mean that the electrical field would be zero?

Something like that. It means that the two points on the conductive surface have no "potential" difference between them. So in other words, you could call the surface of a conductor an __________ surface, right? And since the E field is always perpendicular to that kind of surface, what can you say?
 
Oh an equipotential surface! so the electric field would be perpendicular to the surface!
 
(sorry it took me so long I had to leave for physical therapy)
 
KatieD said:
Oh an equipotential surface! so the electric field would be perpendicular to the surface!

Bingo!
 

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