How to Determine Transistion and Emission of a Photon?

[a.a]

how would you determine the transistion an election took in order to emit a photon of given frequency. I've tried it with some of the formulas i can remember but i seem to end up with two variables ninitial and n- finial, which is basically what i am trying to solve for.

 

[yaychemistry]

Are you speaking about electronic transitions in Hydrogen-like atoms? E.g. with the energy formula E_n = 13.6\textrm{eV}\frac{Z^2}{n^2}. Unless you are given more information to determine n initial or n final you will have two unknowns with one equation.
In that case you aren't guaranteed to have a unique solution, but because n is discrete it is likely there is one set of n's which give you the right answer for "reasonably" low n's. In this case you'll have to do a guess and check strategy.

While this might seem a poor question to put in homework because it is underspecified it actually reflects the challenges that early spectroscopists had in determining the Rydberg formula.

I hope that helped

 

[a.a]

so we would have to do trial and error to find n initial and n final?
dat might take a while, the formula i used was:
delta E = Rh( 1/n-initial^2 - 1/n-finial^2)
and E= hf to find delta E