Re: induced emf again

["John S. Denker" <jsd@MONMOUTH.COM>]

Ludwik Kowalski wrote:
> Are you saying
> that  two forces, q*v*B and q*E, are equal only
> when the current is zero?

I don't see why this question comes up.
 -- If q*v*B is equal to q*E, it's an unusual special case.
 -- If either of them is related to the induced current,
    it's an unusual special case.

This whole thread is muddled.  It repeately seems to take
general principles, apply them to a complicated special
case, and then attempt to re-state certain factoids about
the special case as if they were new general principles.

I also suspect there are some tacit attempts to apply
Kirchhoff's "laws" (or intuitive ideas based thereon)
outside their domain of validity.

Let's get a grip.  We know the general principles.  In
particular, we know the induced voltage on a bar moving
through a magnetic field.  We also know the principle of
superposition, and how to apply it if the E field contains
source terms due to charges as well as source terms due
to magnetic induction.

There are one or two right ways to analyze the moving bar.
We know what they are.

There are infinitely many wrong ways to analyze the moving
bar.  Do we need to discuss each of them separately?

In a system with N details, you can come up with N factorial
special cases where some of the details are coincidentally
related to some of the other details.  But it is a waste of
time to hypothesize that there is some deep meaning or new
general principle reflected in these coincidences.  Humans
have a strong predilection to find pseudo-patterns when no
real patterns exist;  this is right up there with clothing
and religion on the list of "cultural universals".  Part of
scientific training is to recognize and rein-in this predilection,
so as to not waste time pursuing hypotheses that have no chance
of panning out.

The White Queen believed six impossible things before breakfast.
I've believed thirty or forty.  The trick is to winnow them
quickly and focus resources on the hypotheses that have a
reasonable chance of being useful.