- #1
fball558
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Homework Statement
i am reviewing for a physics exam tomorrow. they posted practice problems and with answers but don't show you how to get the answers. i got most the problems but there are a few I am not sure so figured i would come here and see if you guys can explain it to me.
the problem is as follows
Problem 3: A certain metal is kept at a very low temperature. It is observed that when
photons with energies between 0.2 and 0.9 eV strike the material, only photons of 0.3 eV,
0.4 eV and 0.7 eV are absorbed. If the metal is heated to the point that 0.7 eV photons are
emitted, what photon energies would you expect to observe?
A. 0.3 and 0.7 eV
B. 0.1, 0.3, 0.4, and 0.7 eV (correct answer)
C. 0.3, 0.4 and 0.9 eV
D. 0.2, 0.4, and 0.7 eV
E. 0.7 and 0.9 eV
i don't even know where to start or how they got this answer. second line syas something about 0.2 - 0.9 eV and the answer has a 0.1??