## Atomic Spectra Post-Module Assessment

$c=\lambda v$

Baoying Li 1B
Posts: 113
Joined: Sat Aug 17, 2019 12:18 am

### Atomic Spectra Post-Module Assessment

Hey guys. What are the answers to #40, 43.44? And can you show the process of how to solve one of them?

Vanessa Chuang 4F
Posts: 51
Joined: Sat Aug 24, 2019 12:18 am

### Re: Atomic Spectra Post-Module Assessment

40: 7.46*10^-6 m
43: 1.22*10^-7 m
44: 9.73*10^-8 m; UV region

To solve 40, you first need to use En = -h/ R n2 to find E6 and E5. Then in order to find the energy difference you subtract the initial energy from the final energy (E5-E6). You'll end up getting -2.66*10^-20 J.
The question is asking for the wavelength of light but you need to find the frequency in order to solve for the wavelength.
Therefore, you use E = h ν to find the frequency (ν ). Since frequency can't be negative, you make the energy difference you got positive and solve.
You'll end up getting 4.02*10^13 Hz.
Then you use that frequency to solve for the wavelength using c = λ ν. Since you know what ν is and since c is a constant, λ (wavelength) is your only variable to solve for.
You'll end up with something like 7.46*10^-6 m.