- #1
physical101
- 47
- 0
Homework Statement
I want to convert wavenumbers into wavelength. The wavenumber is 400cm-1 and i used the expression v=vbar*c to get the frequency in Hz to be 1.2*10^13, I also remembered to convert c into cm/s so that frequency is in its SI units (seconds). I then simply thought that I could use the expression lambda=c/v to get the answer i require and then multiply that answer by 1*10^9 to get my answer in nm instead of ms. I know the answer should be
2500nm but i get 25000nm. Why do i have this factor of 10? where did it come from?
Homework Equations
i began with vbar=400 cm-1
so then i said that
v=vbar*c
v=400*3*10^10
v=1.2*10^13 Hz
I then said that
lambda nm=(c/v)*1*10^9
lambda=(3*10^8/1.2*10^13)1*10^9
lambda = 25000 nm when it should be 2500nm or 2.5um
The Attempt at a Solution
Please see above
I know this forum is used mainly by graduates who set each other calculus based challenges but any help for a simple folk like me would be much appreciated.