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Re: Lenz's Law



Tina,

Here is what I do.

First, if the problem involves an externally
energized coil to create the original B and
changing B and the induced current is also in this
coil, then I think of problem as two identical
superimposed coils ( The driver and the driven).

Second think very very carefully the direction of
change of the magnetic field. The concern is the
difference between:
an upward pointing field that is becoming stronger
(Delta B points up )
and
an upward pointing field that is becoming weaker
(Delta B points down )

Finally, how would I energize a coil so that the
magnetic field it created was in the opposite
direction as the Delta B found above.

Thanks
Roger Haar

***************************************************************
Tina Fanetti wrote:

Hello
Today I was covering Lenz's law in class. I was doing an example and I got all confused and couldn't get the current going the right way.

How do I figure out which way the induced current is going? I have looked in 4 books and they all use the same example. Haliday, Resnick, Walker use I different right hand rule..
the more I read and try to figure out the worse it gets....

Help Please
Tina (feeling dumb)

Tina Fanetti
Physics Instructor
Western Iowa Technical Community College
4647 Stone Ave
Sioux City IA 51102
712-274-8733 ext 1429