Which Electron Transitions in Singly-Ionized Helium Emit Blue Light?

[Jason Gomez]

Which electron transitions in singly-ionized Helium (He+) yield photons in the blue (450-500 nm) portion of the electromagnetic spectrum? What are their wavelengths, and what transitions do they represent?

Homework Equations

hear is the equation I tried to use an equation creator but did not work, sorry;

1/wave length=Z^2*R(1/nf-1/nI)
where Z is the charge, for Helium=2
and R=1.097*10^7 m^(-1)

The Attempt at a Solution

ok, I found the wave length to be 455 nm when nf=5 and nf=4, that is the only one I could find, and I do not understand how to answer the first part. Is the found nf and nI the electron transitions, and what does it mean by what transitions does it represent? Thank you

 

[Jason Gomez]

I just realize that I made the charge on Helium 2, but it should be 1, I think, and then the only nf and nI I can find is 3 and 7 respectively giving wave length of 478nm. I believe I am over thinking the first part and believe the found nf and ni is the transition but I am confused on the last part still.