Re: Lenz's Law?

[Chuck Britton <britton@odie.ncssm.edu>]

> >  Also, he said the demonstration where an aluminum ring is placed on
> >  an iron core stand that is surrounded by a transformer coil does not >
> > truly demonstrate Lenz's Law.  What is your sense on this one, too.
>
> What is demonstrated with the aluminum ring?  I know of a couple of
> things:
>
> One is joule heating from the induced current.
	And cooling the ring in LN2 is an exciting way to show the
decreased resistance at lower T for most metals, as well as illustrating
Ohm's Rule of Thumb that the lowered resistance results in a greater
current being created by the changing magnetic flux. (Faraday's Law of
Induction).


The demos of this that I have seen only send a single pulse of current thru
the coil, making the Lenz's Law explanation more beleivable.

(But then, I had been laboring under the misunderstanding that the inertia
of objects, as measured by their mass, was responsible for their Newton's
First Law behavior.)