Consider two energy levels that characterize the atoms of
Chapter 30, Problem 30.44(choose chapter or problem)
Consider two energy levels that characterize the atoms of a material used in a laser. A population inversion between these two levels __________. (a) has the lower energy level more populated than it normally is and the higher energy level less populated than it normally is (b) is the same thing as a metastable state (c) requires no external source of energy to be sustained (d) has the higher energy level more populated than it normally is and the lower energy level less populated than it normally is
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