Teaching Faraday's law of electromagnetic induction in an introductory physics course

American Journal of Physics

Volumn 74, Issue 4, 2006, Pages 337-343

  Galili, Igal ^a   Kaplan, Dov ^a   Lehavi, Yaron ^a  

^a HEBREW UNIVERSITY OF JERUSALEM   (Israel)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 33645668983     PISSN: 00029505     EISSN: None     Source Type: Journal    
DOI: 10.1119/1.2180283     Document Type: Article

References (34)

1. Transformer emf is a less common term denoting the induction emf caused by changes of intensity of the magnetic field, The motional emf is caused by the motion of a conductor in a magnetic field.
2. R. Feynman, R. B. Leighton, and M. Sands, Lectures on Physics (Addison-Wesley, Reading, MA, 1964), Vol. 2, pp. 17-1-17-1-3.
3. A. Einstein, "On the electrodynamics of moving bodies," Ann. Phys. 17, 891-921 (1905).
4. English translation in A. Einstein, The Principle of Relativity (Dover, New York, 1952), pp. 37-65.
5. We surveyed about thirty textbooks on university-level introductory physics course, all published in English during the last 10 years.
6. By "geometrically linear" circuits we mean simple electrical circuits treated in introductory courses including elements such as simple resistors and coils, connected in series or parallel or otherwise.
7. See, for example, H. D. Young and R. A. Freedman, University Physics (Addison-Wesley, San Francisco, 2004), pp. 1106 and 1120.
8. Induction=-(ΔB/Δr)4-vBI sin(v, B). See, for example, J. Touger, Introductory Physics (Wiley, New York, 2006).
9. M. Faraday, Experimental Researches in Electricity (Britannica Great Books, Chicago, 1832/1978), First Series, pp. 265-285.
10. See Ref. 7, Second Series, pp. 286-302.
11. I. E. Tamm, Fundamentals of the Theory of Electricity (Mir, Moscow, 1979), Sec. 112.
12. The scope of introductory physics courses varies among universities and usually does not include Maxwell's equations in differential form. Our treatment remains applicable because it addresses shortcomings in the application of the integral form of the law of induction.
13. L. D. Landau and E. M. Lifshitz, Electrodynamics of Continuous Media (Pergamon, Oxford, 1960), Sec. 63.
14. See Ref. 2, p. 17-2.
15. R. Chabay and R. Sherwood, Electric & Magnetic Interactions (Wiley, New York, 1995).
16. I. Galili and D. Kaplan, "Changing approach in teaching electromagnetism in a conceptually oriented introductory physics course," Am. J. Phys, 65(7), 657-668 (1997).
17. The weak relativistic approximation can be developed if force invariance is allowed. See for example, Ref. 15.
18. The index F denotes the frame of reference of the moving rectangular frame.
19. See, for example, H. Benson, University Physics (Wiley, New York, 1996).
20. This definition justifies neglecting the drift velocities of the charges free to move.
21. See, for example, Ref. 9.
22. Reference 2, p. 17-3.
23. This argument is qualitative. Similar to the velocities of the wheel of a moving car near the point of touching the road, which is not the velocity of the car relative to the road, the velocities of the material of the rocking plates are not equal to the velocity of the touching point P. See also F. Munlay, "Challenges to Faraday's flux rule," Am. J. Phys. 72(12), 1478-1483 (2004).
24. E. M. Purcell, Electricity and Magnetism (McGraw-Hill, New York, 1985), p. 272.
25. G. I. Cohn, "Electromagnetic induction," Electr. Eng. 68(5), 441-447 (1949)
26. (thanks to Bruce Sherwood). P. J. Scanion, R. N. Henriksen, and J. R. Allen, "Approaches to electromagnetic induction," Am. J. Phys. 37(7), 698-708 (1969)
27. ascribed an equivalent case to F. A. Kaempffer, Elements of Physics (Blaisdell, Waltham, MA, 1967), p. 164.
28. This statement is valid only for translational movement. For rotation (unipolar generator) the argument about the absence of relative motion for the absence of emf does not hold (see Ref. 9).
29. See Ref. 2, p. 17-1.
30. See, for example, D. Halliday and R. Resnick, Fundamentals of Physics, 3rd ed. (Wiley, New York, 1988), p. 745.
31. For example, "We can obtain the same relation [emf of induction] in another way without the use of Faraday's law," D. C. Giancoli, Physics for Scientists and Engineers, 2nd ed. (Prentice Hall, Englewood Cliffs, NJ, 1988), p. 677.
32. This account is equivalent to using the Lorentz force, but needs additional and somewhat artificial assumptions for the case of magnet rotation (as in unipolar induction).
33. J. C. Maxwell, A Treatise on Electricity and Magnetism (Dover, New York, 1954), Vol. 2, Chap. III, pp. 179-189.
34. For example, a similar derivation can be found in W. K. H. Panofsky and M. Phillips, Classical Electricity and Magnetism (Addison-Wesley, Reading, MA, 1962), pp. 160-163.