## How to use the Rydberg Formula? [ENDORSED]

$c=\lambda v$

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Ryan Fang 1D
Posts: 53
Joined: Sat Jul 22, 2017 3:00 am

### How to use the Rydberg Formula?

In a Rydberg equation problem, you are given two n values. The Rydberg formula is: frequency = R(1/n1^2 - 1/n2^2). How do I know which n comes first in the Rydberg formula? How do I know which one is n1 and which one is n2?

Sarah Rutzick 1L
Posts: 50
Joined: Tue Oct 10, 2017 7:13 am

### Re: How to use the Rydberg Formula?  [ENDORSED]

You want n1 to be the energy level that the electron drops to, and n2 to be the energy level that the electron drops from, so n1 will be the smaller n value and n2 will be the larger n value.

skalvakota2H
Posts: 52
Joined: Sat Jul 22, 2017 3:01 am

### Re: How to use the Rydberg Formula?

Since the Rydberg formula is essentially a change equation describing the change in energy from one energy level to another, one will always calculate the difference as final minus initial. This is one way to remember that in the parenthesis, n2 is the final energy level for the electron.

Sabah Islam 1G
Posts: 50
Joined: Sat Jul 22, 2017 3:01 am

### Re: How to use the Rydberg Formula?

You can also use the equation: En=-hR/n^2 to find the energy of a energy level and do that for the final and initial energy levels and subtract the initial energy from the final energy to find the energy difference between two energy levels. It is always final energy level - initial energy level.

Jason Liu 1C
Posts: 52
Joined: Fri Sep 29, 2017 7:04 am

### Re: How to use the Rydberg Formula?

I don't see the Rydberg formula on the constants and equations sheet. Does that mean we will have to memorize it? I also don't quite understand why there is a negative sign in the formula En=-hR/n^2

Justin Lai 1C
Posts: 50
Joined: Fri Sep 29, 2017 7:04 am

### Re: How to use the Rydberg Formula?

I'm pretty sure all equations that we need on the test will be provided on the equations sheet. It is negative because some people switch the n1 with the n2 and to keep frequency as a positive number, they use the negative sign.

Allyson Charco Dis1G
Posts: 21
Joined: Fri Sep 29, 2017 7:04 am

### Re: How to use the Rydberg Formula?

Potentially aren't there two formulas which are v=-R [1/n1^2 - 1/n2^2] and you could also use the equation that professor Lavelle went over in class in which we calculate n 1 and 2 separately and then subtract them. It all come to which preference you prefer the first equation requires less computation. And all the variables have a value
n= is the energy level
R= rdyberg constant : 3.29x10^15 Hzs^-1
h=6.626x10^-34
And in the problems we are either given n or v to calculate whatever it is they are asking for. But anyways both formulas work and should give you the same answer.
Oh i forgot to include the other equation which professor Lavelle used in class.
E sub n= -hR/n^2

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