Question

Yellow light emitted from a sodium lamp has a wavelength (λ) of 580 nm. Calculate the frequency (v) and wave number (bar v) of the yellow light.

Answer 1

Wavelength, λ = 580 nm = 580 x 10^-9 m

Velocity of light, C = 3 x 10⁸ ms^-1

Frequency, v = C/λ = {3 x 10⁸ ms^-1}/{580 x 10^-9 m} = 5.17 x 10¹⁴ s^-1

= 5.17 x 10¹⁴ Hz or s^-1

Wave number, bar v = 1/λ = {1}/{580 x 10^-9 m} = 1.72 x 10⁶ m^-1