Re: Error in Wikipedia article: Faraday's law of induction

On 12 Jul, 12:19, phil-news-nos...@xxxxxxxx wrote:
It seems there is an error in this Wikipedia article:

   http://en.wikipedia.org/wiki/Faraday%27s_law_of_induction

Faraday's law says the induced EMF is in proportion to the rate of CHANGE
(my emphasis) of the magnetic flux.  The article describes this much OK..
Later on, the article then says:

    In the case of motional EMF, the idea is to move all or part of the
    circuit through the magnetic field, for example, as in a homopolar
    generator.

But this last case is a situation where the magnetic flux does not change..
Isn't this the aspect that Faraday saw as a paradox because it did not obey
his law of induction?  Apparently he realized that no flux change happened
when he rotated the magnets with the rotating disk in his unipolar generator.

As I understand all this, there are TWO ways to induce electricity from a
magnetic field:

1.  A conductor at a right angle to the magnetic field alignment experiencing
    a change in the magnetic field flux density (strength).  [Faraday's law
    of induction]

2.  Motion of a conductor at right angle to the magnetic field alignment and
    simultaneously at right angle to the line of the conductor.  [Fleming's
    right hand rule, Lorentz force law]


The article seems to be trying to convert everything into one.

Which is correct, as far as Faraday's Law is concerned. The induced
EMF around a closed circuit is equal to the rate of change of flux
through the circuit and independent of whether it's the conductor or
the magnetic filed which is "moving".


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