Re: [Phys-L] circular definition of "success" .... was: standard DC circuits

[Jeffrey Schnick <JSchnick@Anselm.Edu>]

By charge separation, I understood Bruce to mean that there is a certain tiny amount of positive charge on the positive terminal of the battery and the same amount of negative charge on the negative terminal.  This charge creates the electric field that is characterized by the constant electric potential difference between the terminals.  To maintain that constant electric potential difference, the battery has to maintain that charge distribution.  The total amount of charge that has flowed through the battery to date does not seem to be relevant to the question of charge separation.
________________________________________
From: Phys-l [phys-l-bounces@phys-l.org] on behalf of John Denker [jsd@av8n.com]
Sent: Tuesday, December 03, 2013 7:05 PM
To: Phys-L@Phys-L.org
Subject: Re: [Phys-L] circular definition of "success" .... was: standard DC circuits

As is usual in this forum, we are having four different conversations,
discussing stuff that is appropriate for ...
 -- the introductory high-school physics course;
 -- the introductory college electrical-engineering course;
 -- the second year of the calculus-based college physics course;
 -- ourselves and other who are truly deeply madly in love with
  the microscopic physics details.

All that is 100% fine, so long as we keep track of which conversation
is which.  In a recent message I was not as clear about this as I
should have been.


On 12/03/2013 01:26 PM, Jeffrey Schnick wrote:
> > > http://www.av8n.com/physics/img48/battery-operating-curve.png
> What charge is plotted here? The charge on the positive terminal of
> the battery?  How is the charge changed?  How is the charge
> measured?

Good question.  Let me clarify that I had in mind the /engineering/
notion of charge.  Imagine a world where Kirchhoff's laws apply.
The only possible relevant charge is

            Q = ∫ I dt                              [1]

where I(t) is the current flowing through the battery.

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