Faraday’s Law and Magnetic Induction: Cause and Effect, Experiment and Theory
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Physics Department, Lancaster University, Lancaster LA1 4YB, UK
2
Cockcroft Institute, Keckwick Lane, Daresbury WA4 4AD, UK
Physics 2020, 2(2), 150-163; https://doi.org/10.3390/physics2020009
Received: 18 March 2020
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Revised: 21 April 2020
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Accepted: 27 April 2020
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Published: 6 May 2020
(This article belongs to the Section Physics Education)
Faraday’s Law of induction is often stated as “a change in magnetic flux causes an electro-motive force (EMF)”; or, more cautiously, “a change in magnetic flux is associated with an EMF”. It is as well that the more cautious form exists, because the first “causes” form can be shown to be incompatible with the usual expression , where is EMF, is a time derivative, and is the magnetic flux.This is not, however, to deny the causality as reasonably inferred from experimental observation—it is the equation for Faraday’s Law of induction which does not represent the claimed cause-and-effect relationship. Unusually, in this induction scenario, the apparent experimental causality does not match up with that of the mathematical model. Here we investigate a selection of different approaches, trying to see how an explicitly causal mathematical equation, which attempts to encapsulate the experimental ideas of “a change in magnetic flux causes an EMF”, might arise. We see that although it is easy to find mathematical models where changes in magnetic flux or field have an effect on the electric current, the same is not true for the EMF.
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Keywords:
Faradays law; cause; effect; experiment; mathematics; model
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Externally hosted supplementary file 1
Link: https://arxiv.org/abs/1705.08406
Description: The version of this paper at arxiv:1705.08406 has additional commentary.
MDPI and ACS Style
Kinsler, P. Faraday’s Law and Magnetic Induction: Cause and Effect, Experiment and Theory. Physics 2020, 2, 150-163. https://doi.org/10.3390/physics2020009
AMA Style
Kinsler P. Faraday’s Law and Magnetic Induction: Cause and Effect, Experiment and Theory. Physics. 2020; 2(2):150-163. https://doi.org/10.3390/physics2020009
Chicago/Turabian StyleKinsler, Paul. 2020. "Faraday’s Law and Magnetic Induction: Cause and Effect, Experiment and Theory" Physics 2, no. 2: 150-163. https://doi.org/10.3390/physics2020009
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