## Sapling homework Question 8

H-Atom ($E_{n}=-\frac{hR}{n^{2}}$)

Jaclyn Dang 3B
Posts: 72
Joined: Wed Sep 30, 2020 10:02 pm

### Sapling homework Question 8

Hi, I'm not sure where to start on this problem, if anybody can give me the steps along with a quick reasoning/explanation, it'd be highly appreciated!

A blue line is observed at 486.1 nm in the spectrum of atomic hydrogen. Determine the values of n for the beginning and ending energy levels of the electron during the emission of energy that leads to this spectral line.
n1=
n2=

Thank you guys!

RDove_1A
Posts: 65
Joined: Wed Sep 30, 2020 9:48 pm

### Re: Sapling homework Question 8

Hi, so the question is asking about an electron transition. We know that the energy of the photon has to match the change in energy of the electron. So you will want to use E(n final)=-hR/n^2 - E(n initial)=-hR/n^2 and set it equal to the energy of the light. It will seem like you have two unknown n values which you wouldn't be able to solve, but since it tells you the line is blue, you know the light is visible and therefore in the Balmer series where the final energy level is n=2. From there you can solve for the other n. Hope this helps!
Last edited by RDove_1A on Tue Oct 20, 2020 10:40 am, edited 1 time in total.

Jenny Lee 2L
Posts: 67
Joined: Thu Oct 08, 2020 12:15 am

### Re: Sapling homework Question 8

I agree with RDove! The only thing I wanted to add is that you also know this is an "emission" of energy from the question, and thus you can further check that your final is n=1 and not n=2. But usually, most questions so far seem to ask for the emission of energy anyway; just wanted to add a small detail.

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