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Re: induced emf again



| . . .
| 2) This realization brings back the initial question. What
| can one do, experimentally, to show that Feynman is
| correct? His arguments are based on gedankenning,
| that is on theoretical considerations. If two effects are
| different then there should exist an experimental way
| of distinguishing between them. Any suggestion?
| . . .
| > > Ludwik Kowalski

The two effects are :
1) Curl(E) = -dB/dt (partial derivative) says a time varying B is a
source of a non-conservative E.
2) A moving charge (even a carrier in a moving conductor) will experience
the force F = q*VxB. This can be used to generate a motional emf around a
closed path.

Direct, simple experiments can show the above facts.

Curl(E) =-dB/dt can be integrated over a surface and (with Stokes theorem)
can lead to the Flux rule: emf = -dPhi/dt. This refers to the emf (around
a closed path) for the nonconservative E field of Curl(E) = -dB/dt. This
is rigorously always true - it follows from the basic (Maxwellian)
physics.

In order to apply the flux rule to the motional emf generated in a moving
conductor you must go beyond Maxwell and explore appropriate paths in the
geometry of your situation and simply notice the result. That this can
always be successfully done is nowhere required by any of Maxwellian
electrodynamics.

What yet needs to be proved?

Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor