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Lenz's Law Demonstration Using an Ultrasound Position Sensor
The Physics Teacher
  • Petru S. Fodor, Cleveland State University
  • Tara Peppard, Cleveland State University
Document Type
Article
Publication Date
8-24-2012
Disciplines
Abstract

One of the very popular demonstrations used in introductory physics courses to illustrate Lenz's law is the “slowly falling magnet.” In its simplest version it requires only a powerful cylindrical magnet and a metal tube, typically of copper or aluminum. When dropped in the tube the magnet takes significantly longer to reach the other end than a geometrically similar but nonmagnetic object. This demonstration has been adapted for use in large classes using a camera to monitor the magnet as it approaches the end of the tube.1 Small versions that can be used for hands-on experiments also have been developed2 or are available commercially.3 This classical demonstration in its various forms almost never fails to impress first-time viewers.

DOI
10.1119/1.4745685
Citation Information
Petru S. Fodor and Tara Peppard. "Lenz's Law Demonstration Using an Ultrasound Position Sensor" The Physics Teacher Vol. 50 Iss. 6 (2012) p. 344
Available at: http://works.bepress.com/petru_fodor/23/