## 1A 15

Maria Poblete 2C
Posts: 102
Joined: Wed Sep 18, 2019 12:15 am

### 1A 15

I'm having trouble with this problem:

In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6 nm. Determine the values of n for the initial and final energy levels of the electron during the emission of energy that leads to this spectral line.

To be quite honest I'm not even sure where to start on this problem. Is 102.6nm the wavelength of the incoming light? Also, how do I know what threshold values each energy level caps at?

Trinity Vu 1D
Posts: 53
Joined: Fri Aug 30, 2019 12:15 am

### Re: 1A 15

102.6 nm is the wavelength of the incoming light which can be used to find the frequency of the light. In order to find the energy values of the levels, you use the Rydberg equation En=-hR/n^2. Using this equation and v=ΔE/h you can rearrange the equations to get v=-R[1/n1^2-1/n2^2]. Since the UV region transition is considered the Lyman series, you know that the transition will end in energy level 1 meaning that n1=level 1. Plug in v, R, and n1 (1) in order to solve for n2 which ends up being 3.

Maya Beal Dis 1D
Posts: 100
Joined: Sat Aug 17, 2019 12:16 am
Been upvoted: 2 times

### Re: 1A 15

102.6 nm is part of the UV spectrum so you know you are using the Lyman series. You first divide the speed of light by the wavelength given to get frequency. You then rearrange the Rydberg Equation and use your calculated frequency to determine n2 is 3.

MMckinney_4H
Posts: 61
Joined: Sat Sep 28, 2019 12:16 am

### Re: 1A 15

I'm not too sure what you mean by "the wavelength of the incoming light" but it really doesn't matter where the radiation is or has come from. We simply need to know that somewhere there is radiation with a wavelength of 102.6 nm and find out the initial and final electron levels that correspond to it. You'd be given the initial in recognizing that for ultraviolet radiation (in the Lyman series) the electron always begins at n=1. By plugging this into the equation you can find the other energy level.

Maria Poblete 2C
Posts: 102
Joined: Wed Sep 18, 2019 12:15 am

### Re: 1A 15

Thank you everyone! This was really helpful.