- #1

Jdraper

- 51

- 0

## Homework Statement

Hi, I've been unable to find a relevant thread for a question that I've been stuck on for a couple of days now.

Here it is;

One of the electromagnetic emission lines for a hydrogen atom has wavelength 389nm. Assiming that this is a line from one of the Lyman (n

_{f}=1 ), Balmer (n

_{f}= 2) or Paschen (n

_{f}=3) series, what is the initial principle quantum number associated with the transitions? The Rydberg energy can be assumed to be 13.6eV

## Homework Equations

ΔE=Ry(1/(n

_{i})

^{2}- 1/(n

_{f})

^{2}))

Ry=13.6eV

This is the formula used to attempt a solution

There is another formula in my notes that may be helpful but i do not understand the symbols within it, it is;

E

_{n,l}= -Ry/(n-δ

_{l})

^{2}

## The Attempt at a Solution

Using the equation ΔE=Ry(1/(ni)2 - 1/(nf)2)) and then equating this change in energy to the energy of light E=hc/λ.

Ry=13.6eV

Then I insert various n

_{f}'s e.g. n

_{f}=1 for Lyman, then i would solve this for n

_{i}to see if i get an integer number, indicating that this is correct. I do this for n

_{f}=1,2 and 3 and I have never got an integer number leading me to believe my method is incorrect.

Any help or insight would be appreciated,

Thanks in advance, John.