The Rydberg equation, with n1=1, predicts an ultraviolet series of spectral lines of atomic hydrogen. Which of the following wavelengths is not predicted by the equation: 1/ = (1.097 x 10(7) m - 1) x (1/n1(2)-1/n2(2)

Question

a)182 nm
b)103 nm
c)97 nm
d) 95 nm
e) 91 nm
I know i posted this yesturday, but when I try to work this I'm not getting any of these choices so I don't know what I'm doing wrong!
We never did these in class, but they're on the homework so I need to know where I'm going wrong.

Answer 1

103 nm is from n1=1 and n2=3
98 nm is from n1=1 and n2=4
95 nm is from n1=1 and n2=5

I can't get 182 nm.

The limiting value for n1=1 and n2=infinity is 10^9/R = 91.5 nm so the wavelength cannot be smaller than this value.

So my choices are a) and e). c) is also not possible as the nearest value is 97.59 nm which rounds to 98 nm.

Answer 2

182.3 comes from 1 and 2(close to 182)
102.55 comes from 1 and 3(close to 103)
97.23 comes from 1 and 4(close to 97)
94.95 comes from 1 and 5(close to 95)
93.76 comes from 1 and 6(not close to 91)
If you had shown your work we could have found the error. You DO need to learn where your mistake is. If you post another one at the top of the board to my attention, and show your work on any one of them, I will find the error for you.

Answer 3

Bob
I still can't get 182!

1/L=1.097 x 10^7 x(1/1^2-1/2^2)

so

1/L=1.097 x 10^7x(1-0.25)

so

1/L=1.097 x 10^7 x0.75

1/L=8227500

L=1.22 x 10^-7 m

or L=122 nm