In article , Roy Lewallen
wrote:

For Reg, only one. For me, an infinite number.

Roy Lewallen, W7EL

H. Adam Stevens wrote:
what?
there are multiple answers?
how many?

"Roy Lewallen" wrote in message
...

The point is that there's no "correct" answer. The voltage between two
points separated in space with the presence of a varying magnetic field
can be pretty much anything you'd like it to be -- the value depends, as
others have pointed out, on the path taken between the points. Only Reg
is able to suspend the principles of electromagnetics and confidently
compute a single answer.

Roy Lewallen, W7EL

Roy, the good point you are making is often hard to get across. I tried
for about forty years to teach multivariable calculus to EE students and
others. Sometimes I succeeded. But some students couldn't get over the
fact that in one dimension, integrals are independent of the path, and so
they expected that to be true in two dimensions, or in three.

It makes things a lot simpler if you believe that all line integrals are
independent of the path, since from that it follows that integrals around
loops are always zero. That makes things like Green's Theorem and Stokes'
Theorem simpler too, since (if you grant that surface integrals involved
are also zero) they simply say that 0 = 0.

Simple isn't always right. Maybe in some other universe, all fields are
conservative, but not in this one.

David, ex-W8EZE and retired math prof

--
David or Jo Anne Ryeburn

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