In this paper, we discuss a simple apparatus and accompanying class activity that we have developed to illustrate the Biot-Savart law. Since students in introductory electricity and magnetism courses often find this law a mathematical mystery, we feel that a simple experiment such as this will provide the students a better understanding of the concepts introduced. By collecting data from several finite segment lengths, students are able to infer the 1/r2 distance dependence of the magnetic field for infinitesimal segments and the 1/r dependence for infinite wires.
REFERENCES
1.
J. Sanny and W. Moebs, University Physics (McGraw-Hill, Boston, 1997).
2.
H.F. Mieners, Physics Demonstration Experiments (Ronald Press Company, 1970); K. Cummings, P.W. Laws, E.F. Redish, and P.J. Cooney, Understanding Physics (Wiley, New York, 2004).
3.
B. J.
Pernick
, “Simultaneous measurement of the straight wire and the Earth's B field
,” Am. J. Phys.
57
, 90
(1989
).
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© 2008 American Association of Physics Teachers.
2008
American Association of Physics Teachers
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