Hydrogen spectrum question

Question

A wavelength of 4.653 um is observed in a hydrogen spectrum for a transition that ends in the nf= 5 level. What was ni for the initial level of the electron?

Answer 1

Why don't you do the Lyman series problem first.  The wiki link gives you the Rydberg formula for the energy levels and wavelengths, which is the exact same thing you need for this problem.