Figure 2: (a) Franck-Hertz Experimental Apparatus; (b) Results for
Element X.
The Franck-Hertz apparatus containing a gas of atoms of element X in Figure 2a produces the I-V curve shown in Figure 2b. (See next page.)
a) What is the minimum energy required to excite an atom of element X?
b) On the axes below, using the least number of energy
states possible, sketch a set of energy levels for the
energy states of element X which explains the behavior of the I-V
curve.
Hint: The lowest energy state is already sketched for you.
Ediag.eps3.5in3in
c) Assuming that all transitions are possible, what wavelengths of
light would be observed in spectroscopic experiments with this
element?
Hint: 
Å.