# Very simple problem about wavelength, just a double check on work

## Homework Statement

radiation with a frequency of 1200cm^-1, calculate the wavelength in meters and the frequency in hertz

wavenumber = 1/λ

freq = c/λ

## The Attempt at a Solution

1200cm^-1 = 1/λ

λ = 8.33*10^-6 m

freq = (3.0 * 10^8)/(8.66*10^-6) = 3.6*10^13 Hz

## Answers and Replies

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SammyS
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## Homework Statement

radiation with a frequency of 1200cm^-1, calculate the wavelength in meters and the frequency in hertz

wavenumber = 1/λ

freq = c/λ

## The Attempt at a Solution

1200cm^-1 = 1/λ

λ = 8.33*10^-6 m

freq = (3.0 * 10^8)/(8.66*10^-6) = 3.6*10^13 Hz
Hi vande060.

Looks good to me, & I'm a spectroscopist.

(I assume that's 1200 cm-1 in a vacuum.)

collinsmark
Homework Helper
Gold Member

## Homework Statement

radiation with a frequency of 1200cm^-1, calculate the wavelength in meters and the frequency in hertz
Do you mean wavenumber?

wavenumber = 1/λ

freq = c/λ

## The Attempt at a Solution

1200cm^-1 = 1/λ

λ = 8.33*10^-6 m

freq = (3.0 * 10^8)/(8.66*10^-6) = 3.6*10^13 Hz
I think that's right. But realize that depending on the context, wavenumber sometimes is defined as 1/λ and sometimes defined as 2π/λ. The above looks right to me assuming that you are using the wavenumber = 1/λ definition, and assuming that you mean the wavenumber is 1200 cm-1.

Thanks, both of you

radiation with a frequency of 1200cm^-1

if its wave number, then your answer is correct?