# Find n using Bohr model

## Homework Statement

A hydrogen atom in an excited state absorbs a photon of wavelength 410 nm. What were the initial and final states of the hydrogen atom.

## Homework Equations

Rydberg equation:
$$\frac{1}{λ}=R_∞(\frac{1}{n{_l}{^2}}-\frac{1}{n{_u}{^2}})$$

## The Attempt at a Solution

Plugging that wavelength into the equation, I still have two unknowns; the lower n and the upper n. Would finding the frequency help? I don't see any equations I could use that would help me find one of those n's.

Thanks

Dick
Homework Helper

## Homework Statement

A hydrogen atom in an excited state absorbs a photon of wavelength 410 nm. What were the initial and final states of the hydrogen atom.

## Homework Equations

Rydberg equation:
$$\frac{1}{λ}=R_∞(\frac{1}{n{_l}{^2}}-\frac{1}{n{_u}{^2}})$$

## The Attempt at a Solution

Plugging that wavelength into the equation, I still have two unknowns; the lower n and the upper n. Would finding the frequency help? I don't see any equations I could use that would help me find one of those n's.

Thanks

No, you can't find one of those n's. You'll have to guess until you find a good match. Try n1=1 first, figure out why that can't work. Then try n1=2. Then you should be able to find pretty good value of n2 just by guessing. I don't know any other way to play this game.

No, you can't find one of those n's. You'll have to guess until you find a good match. Try n1=1 first, figure out why that can't work. Then try n1=2. Then you should be able to find pretty good value of n2 just by guessing. I don't know any other way to play this game.

Oh ok thanks. I thought about guessing, but thought that was a pretty inelegant way to do it, so I assumed there must have been another way. Guess not.

Thanks.