Re: magnetic field of a long straight wire

[Bob LaMontagne <rlamont@POSTOFFICE.PROVIDENCE.EDU>]

"John S. Denker" wrote:

> > Cross products and wedge products both give the correct results, but
> > neither gives insight into the actual physics.
>
> Neither?
>
> Does that mean that equations never give insight into
> the physics of electromagnetism?
>
> If cross products are no good and wedge products are
> no good, do you have anything better to offer?  Or
> should we all just give up and go home?

At the level we are discussing here (an introductory general physics course)
I think the correct term is _neither_. Both approaches give correct numerical
results that can be tested by measuring the forces between wires, the bending
of a stream of electrons in a magnetic field, etc. Insight comes at a much
later and more advanced level when exchange particles and the like are
encountered.

Cross products are good -  wedge products are good - you say po-tay-to and I
say po-tah-to! Both products are devices, not explanations.

Bob at PC
(B.T.W. - The Pierre Puzzle site is wonderful - well done!)