Re: Electric Potential

[Michael Edmiston <edmiston@BLUFFTON.EDU>]

I believe the question Tina is refering to contains a simple typographical
error.  The problem, when typed correctly, is a valid and it is a very
commonly posed question.  To fix the problem, simply remove the word
"difference."

If students understand that a region of zero electric field can have
non-zero potential, they are on the road to understanding the two concepts.
If they think zero electric field implies zero potential, then they have
some conceptual bugs that need worked out.

This problem is frequently discussed in textbooks alongside a discussion of
van de Graaff generators.  If a van de Graaff generator is operating, and we
define earth potential as zero, then the ball and the whole space inside the
ball is at very high potential.  But the electric field inside the ball is
zero.


Michael D. Edmiston, Ph.D.              Phone/voice-mail:       419-358-3270
Professor of Chemistry & Physics        FAX:                    419-358-3323
Chairman, Science Department            E-Mail                  edmiston@bluffton.edu
Bluffton College
280 West College Avenue
Bluffton, OH 45817


> Tina Fanetti wrote:
>
> The question is from Peer Instruction by Mazur.  It is on page 233, #5.
>
> This is the question
> "If the electric field E equals zero at a given point, must the potential
> difference V also equal zero at that point?  Give an example to prove your
answer."