Re: Electric Potential

[Joseph Bellina <jbellina@SAINTMARYS.EDU>]

I'm not going to speak for Mazur..but I think you need to remember that
these are questions meant to encourage speculation and discussion in a
pair-share format.  So perhaps the conversation would go exactly as this
is going...thus highlighting the distinction between potential
difference and potential.

joe

On Wed, 6 Feb 2002, Hugh Haskell wrote:

> At 11:42 -0600 2/6/02, 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."
> >
> > That is the exact question.
> Then I am afraid that Mazur has written a very poorly-worded
> question. As JD has pointed out, a potential difference can only
> exist *between* two points, not *at* a single point.
>
> If a zero of potential had been established at some previously
> designated point, then the question could be asked, "must the
> potential V [relative to the previously designated zero point] also
> equal zero at that point?"
>
> Since the location of the point at which the potential can be defined
> to be zero is arbitrary, it is clear that there is no requirement for
> the potential relative to that arbitrary point must be zero just
> because the field happens to be.
>
> Hugh
> --
>
> Hugh Haskell
> <mailto://haskell@ncssm.edu>
> <mailto://hhaskell@mindspring.com>
>
> (919) 467-7610
>
> Let's face it. People use a Mac because they want to, Windows because they
> have to..
> ******************************************************

Joseph J. Bellina, Jr.               219-284-4662
Associate Professor of Physics
Saint Mary's College
Notre Dame, IN 46556