# Determine electronic transitions by the emitted wavelength?

 P: 2 1. The problem statement, all variables and given/known data What is the electronic transition of He II when it emits 468.6 nm photon. 2. Relevant equations $$\frac{1}{\lambda}=4R\left(\frac{1}{m^2}-\frac{1}{n^2}\right)$$ 3. The attempt at a solution I know it is a pashen-alpha line from googling but I don't know how to find that from this equation with two unknowns. I know the energy levels are discrete so there is probably only one transition that makes this wavelength. Don't know why He II and not He I so I might be missing something.