The posted method using internal reflection in a prism with three polished
sides was a neat variation on an old standard. However, some of us are on
a limited budget and buy the prisms with only two polished sides, the
third side being frosted.
Here's a variation not (to my knowledge) mentioned in any commercial lab
manuals. By measuring the deviation angle, *and* the angle of reflection
from the first face, for a wide range of incident angles, one can
construct a nice curve of deviation angle vs. incident angle. The results
are very satisfying (compared to dispersion curves shown in textbooks) and
are more interesting because they show a fundamental property of the
glass, one for which there's no simple equation. The curve also shows
*why* the minimum deviation method is so good if you simply want to find
the index of refraction at any chosen wavelength.
-- Donald
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Dr. Donald E. Simanek Office: 717-893-2079
Prof. of Physics Internet: dsimanek@eagle.lhup.edu
Lock Haven University, Lock Haven, PA. 17745 CIS: 73147,2166
Home page: http://www.lhup.edu/~dsimanek FAX: 717-893-2047
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