Answer:
I'm assuming the question is asking when it "jumps" from level 2 to level 1. In which case: 1/λ = Rh(1/nf^2 - 1/nfi^2) = 1.10x10^7 (1/1^2 - 1/2^2) = 1.10x10^7 ( 1 - 0.25) = 1.10 x10^7 (0.75) λ = 1.21 x 10^-7 m The wavelength produced will be about 1.21 x 10^ -7 m, or 121 nm.
