A) Consider a Hydrogen atom. Show a calculation of the *wavelength* of the light emitted when an electron drops from the n=3 to the n=2 state, to four significant figures. (Important: start with the energies of these states in your calculation, to four significant figures! This is needed for part B. No credit for simply using the Rydberg shortcut.)

B) It turns out that in a deuterium atom (hydrogen with one extra neutron) the energy levels are slightly shifted. The n=3 state is about 4.0 meV lower energy than in Hydrogen, and the n=2 state is about 8.5 meV lower energy than in Hydrogen. (meV = milli electron Volts) Find the wavelength of the light emitted by the n=3 to 2 transition in Deuterium. C) Explain in about three sentences of detail, along with a quick sketch, an experiment you could perform to see the slight difference between the light coming from Hydrogen (part A) and the light coming from Deuterium (part B). No numbers or calculations are needed in this part.