The photoelectric effect is one of the key experiments taught during first- or second-year university and high school modern physics courses. It is usually the first experiment to introduce light quantization and the concept of photons as “packets of energy.” Here, we want to point out a widespread mistake concerning the interpretation of the saturation current at constant light intensity that is found even in some classic hardback literature. Although this is usually overlooked, it can weaken the conclusions a student can draw from the correct understanding of the experiment.
References
1.
For example, the following figures and related text explanations all make the pointed-out mistake:
Paul A.
Tipler
and Ralph A.
Llewellyn
, Modern Physics
, 6th ed. (W. H. Freeman and Company
, New York
, 2012
), Fig. 3.9;Hugh D.
Young
and Roger A.
Freedman
, Sears and Zemansky’s University Physics with Modern Physics
, Vol. 2
, 12th ed. (Pearson
, 2008
), Fig. 38.5;Stephen T.
Thornton
and Andrew
Rex
, Modern Physics for Scientists and Engineers
, 4th ed. (Brooks/Cole
, Boston
, 2013
), Fig. 3.13;Arthur
Beiser
, Concepts of Modern Physics
, 6th ed. (McGraw-Hill
, New York
, 2003
), Fig. 2.11;R.
Knight
, Physics for Scientists and Engineers
(Pearson
, San Francisco
, 2004
), Fig. 38.3; note that this mistake is corrected in later editions of Knight.2.
3.
S. B.
McKagan
, W.
Handley
, K. K.
Perkins
, and C. E.
Wieman
, “A research-based curriculum for teaching the photoelectric effect
,” Am. J. Phys.
77
, 87
–94
(Jan.
2009
). The simulation is available at https://phet.colorado.edu/en/simulation/photoelectric (accessed in October 2018) as part of the PhET Interactive Simulations project at the University of Colorado Boulder.4.
R. N.
Steinberg
, G. E.
Oberem
, and L. C.
McDermott
, “Development of a computer-based tutorial on the photoelectric effect
,” Am. J. Phys.
64
, 1370
–1379
(Nov.
1996
).© 2019 American Association of Physics Teachers.
2019
American Association of Physics Teachers
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