Re: B and electric charge

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

On Thu, 3 Jan 2002, Ludwik Kowalski wrote:

> Jack asked (his full message is shown below again)
>
> > OK, so the force law gives the constant in terms of C.  So I
> > need a measure of C that is independent of the force law.
> > Did I miss something?
>
> You are assuming (as most textbook authors) that A is known
> before C. In that case k is not used to define C, it must come
> from a measurement (because all other units in the force law
> already exist). In the sequence I plan to follow this spring the
> Coulomb's law first appears as a proportionality equation.
> How else can it be when Q has no units? The "fudge factor",
> ~9,000,000,000 will be then introduced to define coulomb.
        I don't understand your answer.  My question stands on its own,
and contains no such assumptions.  You use the force law to define C.
Your construction must go something like this:  I have a set of charges.
I pick a standard charge, which enables me to define equal charges (2
charges that have the same repulsive force from the standard, at the
same distance).  Now I pick a "fudge factor", let's make it 25.  Now
I have a definition of "Coulomb".
        Let's go in baby steps, and this is step 1.  Am I with you so
far?  Importantly (using your words) the size of the fudge factor is
arbitrary.
                        Regards,
                                Jack