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ERIC Number: EJ864415
Record Type: Journal
Publication Date: 2009-Nov
Pages: 3
Abstractor: As Provided
Reference Count: 0
ISSN: ISSN-0031-921X
A Simple Demonstration of Back emf
Turner, Lou
Physics Teacher, v47 n8 p513-515 Nov 2009
In discussing motors, one college textbook says, "As the coil (of a motor) rotates in a magnetic field, a back emf is generated that tends to counter the emf that supplies the current." This is a true statement, but it does little to enhance student understanding of how and why it is created. In this paper, I will explain how to take students step by step through the creation of what the experts call "back emf" and then describe a simple experiment that clearly demonstrates its existence.
American Association of Physics Teachers. One Physics Ellipse, College Park, MD 20740. Tel: 301-209-3300; Fax: 301-209-0845; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education; Postsecondary Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A