## spectral lines

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ConnorRazmaDis2I
Posts: 55
Joined: Fri Sep 28, 2018 12:26 am

### spectral lines

I've seen two versions of the same formula: one is v = R(1/n1^2 -1/n2^2). The other is 1/wavelength = R(1/n1^2 -1/n2^2). I was just wondering which of these two equations is correct and what's its main use is for

Samantha Ito 2E
Posts: 64
Joined: Fri Sep 28, 2018 12:29 am

### Re: spectral lines

I've seen the equation written both ways too and I think that both are correct. This formula is mainly used to determine the wavelength of light emitted by an electron moving between the energy levels of an atom.

Madison Gil 3D
Posts: 32
Joined: Fri Sep 28, 2018 12:23 am

### Re: spectral lines

In what type of problems will we need to use this equation and does anyone know if we will be tested on this on the 2nd test?

Samantha Ito 2E
Posts: 64
Joined: Fri Sep 28, 2018 12:29 am

### Re: spectral lines

Also, I think that the Rydberg constant can be written in Hz or m^-1 depending on which formula you want to use.

Samantha Ito 2E
Posts: 64
Joined: Fri Sep 28, 2018 12:29 am

### Re: spectral lines

Depending on what is given, it can be used to determine the frequency, wavelength, or the other energy level. I don't know for sure whether or not it will be on the 2nd test, but I think it is likely that it will be.

Ariel Cheng 2I
Posts: 67
Joined: Fri Sep 28, 2018 12:29 am

### Re: spectral lines

Both work since wavelength is the inverse of frequency. It just depends on what you are trying to solve for in the problem! I think that something of this topic will most likely appear on the exam.

Chem_Mod
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### Re: spectral lines

Both equations are fine (1/lambda is called a wavenumber, but you don't need to know that), Dr. Lavelle wants you using ∆E=Ef-Ei where E=-hR/n^2 to solve these types of problems, not the Rydberg.

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