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[Phys-L] W lamps, emissivity, black body, Wien, etc.



A previous post discussed the invalidity of qualitatively demonstrating
Wien's law with an incandescent lamp and spectroscope (e.g. Project
Star). The only reasonable solution I've found is Pasco's Black Body
Experiment. [ex 9920 -- p. 402 of 2004 catalog] {Where is Vernier?}

Pasco's system is valid, but only qualitatively. This is because they
use a common W incandescent lamp as a source. I'd known for some time W
isn't a flat gray body. That this is the case was graphically (both
senses!) demonstrated when Dr. Crooker (NPS) attempted to fit the
spectrum generated by Pasco's Black Body experiment they recently
acquired for Modern Physics demonstration.

Has any one (out there) used Pasco's or other? And w/ what result?

In searching for Pasco's webb description, I found another who had a
problem w/ the experiment:

http://find.uchicago.edu/~pryke/logbook/20021218/
<http://find.uchicago.edu/%7Epryke/logbook/20021218/>


bc, Chi Square advocate.

p.s. Using available (e.g. Levi, A Guide To Optical System Design V.1)
tables, one may "massage" the data and obtain a better fit, I think.