Yellow light emitted from a sodium lamp has a wavelength `(lamda)` of 580 mm. Calcualte the frequency (v) and wavenumber `(vec v)` of yellow light.

Explanation

We know that `c = v lamda`
` 3 xx 10 ^(8) ms (-2) = v xx 580 xx 1 ^(-9) m`
`c = ( 3 xx 10 ^(8))/( 580 xx 10 ^(-9)) s ^(-1) = 5. 17 xx 10 ^(14) s ^(-1)`
Frequency of yellow light `= 5. 17 xx 10^(14) s ^(-1)`
(ii) We know that `vec v = (1)/(lamda ) , vec v = ( 1)/( 580 xx 10 ^(-9) m ) = 1. 72 xx 10 ^(6) m ^(-1)`
Wavenumber of yellow light `= . 72 xx 10^(6) m ^(-1)`