## spectral lines

$c=\lambda v$

505612629
Posts: 44
Joined: Wed Sep 30, 2020 9:43 pm

### spectral lines

When solving for wavelength of emitted electromagnetic radiation, does the initial n level go as n1 or n2 in the equation "R*(1/n^2"1"-1/n^2"2")?

Arti_Patel_3H
Posts: 101
Joined: Wed Sep 30, 2020 9:38 pm

### Re: spectral lines

It depends on whether light was emitted or absorbed. If absorbed, n1 (initial) would be a lower number than n2 (final). If emitted, n1 would be a greater number than n2.

Nicole Attiq 3D
Posts: 55
Joined: Wed Sep 30, 2020 9:35 pm

### Re: spectral lines

A good tip that my TA told me is to always put the bigger number first when using Rydberg's equation since you will always need to get a positive value. For example, if you know n=1 and the electron jumped up some energy levels, you should put (1/1^2) first since you know whatever the value of n final is will be smaller than 1. Hope that makes sense!

Posts: 73
Joined: Wed Sep 30, 2020 9:34 pm

### Re: spectral lines

I agree with the other responses. Whichever n is a smaller number should be n1 and the larger n should be n2 so that when you plug it into the equation and subtract the inverses of both of them, you end up with a positive number. It will just be easier for you that way.

Pranav Daggubati 3C
Posts: 109
Joined: Wed Sep 30, 2020 9:35 pm

### Re: spectral lines

for emission, n1 is usually the smaller one because that results in a bigger fraction, which makes the whole thing positive

Ava_Basileo_2J
Posts: 16
Joined: Wed Sep 30, 2020 9:42 pm

### Re: spectral lines

Your equation seems to be indicating that the electron is going from n=2 to n=1, because the equation is set up so that "Change in energy = final energy - initial energy". Also, it's helpful to remember that when the electron goes up an orbital the electron is absorbing energy and when it is going down an electron it is emitting energy (negative).

AlbertGu_2C
Posts: 86
Joined: Wed Sep 30, 2020 9:34 pm

### Re: spectral lines

It would depend on the direction relative to which the electron moved up and down the energy levels.