Publication: A simple apparatus for demonstrating how light rays emanate from a point source
Issued Date
2009-04-01
Resource Type
ISSN
19434928
0031921X
0031921X
Other identifier(s)
2-s2.0-85007574363
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Mahidol University
Rights Holder(s)
SCOPUS
Bibliographic Citation
Physics Teacher. Vol.47, No.4 (2009), 243-245
Suggested Citation
Kreetha Kaewkhong, Narumon Emarat, Kwan Arayathanitkul, Alex Mazzolini A simple apparatus for demonstrating how light rays emanate from a point source. Physics Teacher. Vol.47, No.4 (2009), 243-245. doi:10.1119/1.3098212 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/28348
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Title
A simple apparatus for demonstrating how light rays emanate from a point source
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Abstract
A point source of light sends out light rays in all directions and in straight lines. This is an important concept for all students who study elementary optics at the high school level. Most physics textbooks discuss this topic only briefly.1-6 They usually explain the concept by using two-dimensional diagrams even though a three-dimensional discussion may be more instructive. Much of the commercial demonstration equipment that can be used to explain this concept is very expensive (e.g., the optics kit from Suksapan Panit Company7 in Thailand costs approximately $70 U.S.). This and similar optics kits show that light propagates in straight lines but do not represent where the light beams come from. Because it is an abstract idea, most students still have considerable misunderstanding about this concept.8-F14 This paper describes an effective but inexpensive (approximately $20 U.S.) apparatus to illustrate the behavior of light rays emitted isotropically from a point source of light. The apparatus is simple and is intelligible to students.