Re: Induced E Fields in Solenoids

["Donald E. Simanek" <dsimanek@eagle.lhup.edu>]

On Tue, 14 Jan 1997, Eugene P. Mosca wrote:

> Let B denote the field due to the current I in the solenoid.  Consider the
> emf induced around a circular path C that is coaxial with the solenoid.
[snip]

Which is summed up in the compact form of Lenz's law: The induced emf acts
in such a direction as to oppose the *change* causing it.

For the purists: Induced currents produce magnetic fields that tend to
oppose the flux changes that induce those currents. (From a textbook.)

I don't like the phrase 'tends to'. My mind translates that as 'wants
to', or 'would if it could' and then I wonder "Well, does it, or doesn't
it, and how much?"

If the current is increasing, the induced emf acts to slow that
rate of increase.

	-- Donald

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Dr. Donald E. Simanek                            Office: 717-893-2079
Prof. of Physics                    Internet: dsimanek@eagle.lhup.edu
Lock Haven University, Lock Haven, PA. 17745          CIS: 73147,2166 
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