Re: funny capacitor (EUREKA ?)

[Bob Sciamanda <trebor@VELOCITY.NET>]

----- Original Message -----
From: "John S. Denker" <jsd@MONMOUTH.COM>
To: <PHYS-L@lists.nau.edu>
Sent: Thursday, March 15, 2001 09:54 AM
Subject: Re: funny capacitor (EUREKA ?)
> I wrote:
> . . .
> The laws of physics say the potential of the reference-point can be made
> zero by fiat, independent of the nature of the object (if any) at that
point.
> At 06:39 AM 3/15/01 -0500, Ludwik Kowalski wrote:
>  . . .
> > I would like to know what
> > other teachers think about that concept. I was not familiar with it;
> > would this concept be useful in an introductory physics course?
>
> I would like to hear what others have to say about this.

John,
Ludwik understands that gauge invariance allows you to choose to always
take  a fixed space-point/object to be at zero potential.  He is concerned
that if the electrical state of that space-point/object is influenced by
my localized apparatus, then as my apparatus evolves in time, my gauge is
a function of time.  This will not invalidate the information in my
voltmeter readings taken at any particular time, but would I have got some
additional *time-dependent* information if I had chosen a zero reference
point whose electrical state is unaffected by my apparatus?

Bob Sciamanda
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor