Faraday's Law


by Gza
Tags: faraday
Gza
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#1
Jun20-04, 04:15 AM
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Why is it that a changing magnetic flux through a surface should induce an emf? I know that the emf is from a non-conservative electric field, but how exactly was this field generated? (if that is the correct expression for it)
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Locrian
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#2
Jun22-04, 09:57 AM
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When someone gives you an answer as to why this happens, won't you just want to know why whatever answer they gave happens? What will this explanation tell you, exactly?

In my humble opinion whether you accept a paradigm a famous scientist offers you shouldn't depend on whether there is a more fundamental explanation proposed later, but instead depend on wether you can verify it to be a good predictor - which with Faraday's Law is easy to do.
tavi_boada
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#3
Jun22-04, 10:40 AM
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THe apearance of the emf is due to the transformation of the B field to the reference frame of the wire. The transformation laws are governed by the Lorenz equations. I guess this explanation ( given in more detail) is a more fundamental and satisfactory one. Dont forget Faraday was an experimental guy. It's an experimental law

pmb_phy
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#4
Jun22-04, 11:58 AM
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Faraday's Law


Quote Quote by Gza
I know that most people are all too willing to take whatever some famous scientist says on faith ...
I've never met a physicist who took anything on faith. To be honest, I don't recall anyone who seriously studies science taking anything on faith.
..and simply learn their theories without thinking what they mean, ..
I've also never met anyone who seriously studies science who didn't think when learning a theory.
Why is it that a changing magnetic flux through a surface should induce an emf?
You've never learned it because nobody knows the answer to that question. I.e. it's one of Maxwell's equations and those equations are postulates, i.e. not derivable from from other postulates.

For details please see - http://rustam.uwp.edu/202/lec18_19.html

Pete
Gza
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#5
Jun22-04, 04:18 PM
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When someone gives you an answer as to why this happens, won't you just want to know why whatever answer they gave happens? What will this explanation tell you, exactly?

This is the nature of an inquisitive mind. If it weren't for people asking why, we would still be in the realm of classical physics, with no motivation to advance.

And I apologize if my original post seemed to be confrontational to anyone; the people on this board are obviously the last people one would expect to take things on faith. It just seemed like a sensible question to ask.
pmb_phy
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#6
Jun22-04, 06:37 PM
P: 2,955
Quote Quote by Gza
And I apologize if my original post seemed to be confrontational to anyone; the people on this board are obviously the last people one would expect to take things on faith. It just seemed like a sensible question to ask.
No problemo! I all the years I've been posting in physics boards on the internet I've seen many people think that physicists are just gulible people who believe anything a prof tells them too. I don't know why people make that assumption so much but it does seem to be a common theme to those people who are not scientists.

Pete


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