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Re: EM Induction - A conceptual question



chuck britton wrote:

Note that the B-field is said to be confined to a concentric circle
with radius LESS than that of the loop.

Note also that the B field is said to be uniform.

Let's ignore the fact that these two are mutually exclusive

Let's not get nit-picky.
The original question described a piecewise-uniform B-field.
Uniform in one area and zero in another. There's nothing
mutually-exclusive or inconsistent or unphysical about this.

MY question is: IF the confined B field expands and contracts while still
being always INSIDE the loop, will an emf be induced.

There will be no induced voltage at the location of the loop.
There will be various induced voltages in various other places.

Why would anybody think otherwise?

And I will SWEAR that I have seen several references to the
quantum limit of magnetic field density, expressed in terms of the usual
gang of fundamental constants. Doesn't this mean that the 'nonexistant'
weber lines are discrete lines???

To the extent that they exist at all, the lines are not, in
general, quantized. The water coming out of a leaky faucet
is quantized in drops, but that does not mean that all water
everywhere is quantized in drops of that size. Similarly,
there are situations (such as superconducting rings) where
one can find quantized amounts of flux, but that does not mean
that all flux everywhere is quantized. Except for regions whose
boundary lies entirely within a superconductor, and possibly a
few other exceptions, you can have any non-quantized amount of
flux you like.

========
I am asking these previous questions also, with the restrictions and
variations stated above.

My previous answer to the previous questions is unchanged.