Electromagnetic induction: How the "flux rule" has superseded Maxwell's general law

被引:0
|
作者
Giuliani, Giuseppe [1 ]
机构
[1] Univ Pavia, Dipartimento Fis, Via Bassi 6, I-27100 Pavia, Italy
关键词
D O I
10.1119/5.0138144
中图分类号
G40 [教育学];
学科分类号
040101 ; 120403 ;
摘要
As documented by textbooks, the teaching of electromagnetic induction in university and high school courses is primarily based on what Feynman labeled as the "flux rule," downgrading it from the status of physical law. However, Maxwell derived a "general law of electromagnetic induction" in which the vector potential plays a fundamental role. A modern reformulation of Maxwell's law can be easily obtained by defining the induced electromotive force as (sic)(l) ((Epsilon) over bar + (v) over bar (c) x (Beta) over bar), where (v) over bar (c) is the velocity of the positive charges which, by convention, are the current carriers. Maxwell did not possess a model for the electric current. Therefore, in his law, he (v) over bar (c) to be the velocity of the circuit element containing the charges. This paper aims to show that the modern reformulation of Maxwell's law governs electromagnetic induction, and the "flux rule" is not a physical law but only a calculation shortcut that does not always yield the correct predictions. This paper also tries to understand why Maxwell's law has been ignored, and how the "flux rule" has taken root. Finally, a section is dedicated to teaching this modern reformulation of Maxwell's law in high schools and elementary physics courses. (c) 2023 Published under an exclusive license by American Association of Physics Teachers.
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页码:278 / 287
页数:10
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