Question

Calculate the frequency and wavenumber of blue light of wavelength 4800A?

Answer 1

Frequency = Velocity / wavelength

= (3 × 10^8 m/s) / (480 × 10^-9 m)

= 6.25 × 10^14 Hz

Wavenumber = 1 / Wavelength

= 1 / (480 × 10^-9 m)

= 2.086 × 10^6 m^-1

Answer 2

Frequency (ν) = c/λ

λ = 480 nm = 4.8 x 10-7 m

Frequency = 3 x 108/ 4.80 x 10-7

 = 6.25 x 1014 Hz

 

wave number = 1/λ

After putting the value of λ in the given formulae 

wave number = 1/4.8 x 10-7 m-1

 = 0.208333 x  10-7 m-1

   = 2.0833 x 10-4 cm-1