## Homework Problem 1.15

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

Sara Sasaki 1K
Posts: 48
Joined: Fri Sep 29, 2017 7:05 am

### Homework Problem 1.15

Hi everyone, I don't think I am understanding the concept of En=-(hR)/(n^2).
In the homework set problem 1.15, I started by solving for the frequency using the given wavelength (102.6 nm), then using the frequency to solve for the energy, and now I'm stuck.
I'm comparing my work to the solutions manual but it's completely different than what I'm doing and I don't quite understand the concept, so any advice or information on how to start the problem would be greatly appreciated!

Leanne Wong 1H
Posts: 50
Joined: Tue Oct 10, 2017 7:13 am
Been upvoted: 1 time

### Re: Homework Problem 1.15

After you solve for frequency, you use Rydberg's formula which is v (frequency) = R($\frac{1}{n1^{2}}$-$\frac{1}{n2^{2}}$). You always assume that n1 = 1, so you just plug in Ryberg's constant, n1 and frequency to solve for n2.

Akash_Kapoor_1L
Posts: 52
Joined: Thu Jul 13, 2017 3:00 am
Been upvoted: 1 time

### Re: Homework Problem 1.15

Can we do this problem without using Rydberg's Formula? I'm trying to solve it with E= -hR/n^2, but I keep getting a decimal number... I'm not sure if I'm just doing the calculation wrong or if there is a problem with my method

Emma Li 2C
Posts: 51
Joined: Fri Sep 29, 2017 7:07 am
Been upvoted: 1 time

### Re: Homework Problem 1.15

For the E=-hR/n^2 method!
I kept getting a decimal number too until I tried making the change in energy (calculated from the given wavelength) negative.

Brandon Fujii 1K
Posts: 51
Joined: Fri Sep 29, 2017 7:04 am

### Re: Homework Problem 1.15

We assume that n=1 because this is a Lyman Series, and the lowest possible energy level is n=1.

For Balmer, the lowest energy level is n=2
For Paschen n=3
For Brackett n=4
For Pfund n=5

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