Re: B and electric charge

[Jack Uretsky <jlu@HEP.ANL.GOV>]

        Here's one waiting for your return:
        How about going in baby steps, though, like you're the teacher and
I am trying to understand what you are doing (not much of a stretch).
        We've agreed on definition of charge, as described previously.
The arbitrary constant is 25 N-m^{2}/C^{2}; an equal charge pair giving
a force of 1 N at a separation of 1 m is 1/5 C.  Now I hear you talking
about currents.  How do I measure a current (I understand that it is
"flowing charge" and 1 A = 1 C/s)?
        How do you answer your student?
                                Regards,
                                        Jack


On Fri, 4 Jan 2002, Ludwik Kowalski wrote:

> Ludwik Kowalski wrote:
>
> > What I would like to discuss is the definition of B.
> > Why do we define it in terms of the EFFECT of the
> > magnetic field and not in terms of what CAUSES it?
> > Instead of introducing B via the Lorentz law (directly
> > or indirectly) we can introduce it via the Bio Savart
> > law. Which way is pedagogically more desirable and
> > why? I have no opinion so far.
>
> Actually the question should have been asked differently.
> Why do we first show what the field does and then how
> it is produced? In other words, why Lorentz first and
> Biot-Savatr later? Would the reversal be desirable or not?
> The formal introduction of B should match the conceptual
> sequence chosen, as it does in most textbooks.
> Ludwik Kowalski

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