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ERIC Number: EJ1025122
Record Type: Journal
Publication Date: 2013-Nov
Pages: 2
Abstractor: As Provided
Reference Count: 6
ISSN: ISSN-0031-921X
On the Intensity Profile of Electric Lamps and Light Bulbs
Bacalla, Xavier; Salumbides, Edcel John
Physics Teacher, v51 n8 p491-492 Nov 2013
We demonstrate that the time profile of the light intensity from domestic lighting sources exhibits simple yet interesting properties that foster lively student discussions. We monitor the light intensity of an industrial fluorescent lamp (also known as TL) and an incandescent bulb using a photodetector connected to an oscilloscope. The light intensity of these sources displays modulation at twice the ac power supply frequency. The familiarity of ac line power supply, commonplace light sources, and simplicity of the setup encourage student confidence, allowing them to think deeper and continually reassess their notions, and if managed can lead to a satisfactory explanation of the observations.
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: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A