The frequency of a photon

Question

The frequency of a 13.0 eV photon is ___x10¹⁵ Hz.?

Answer 1

The Energy of a photon E = 13 eV

E = 13 x 1.6 x 10^-19 J             ( Substitute : 1 eV  = 1.6 x 10^-19 Joules )

E = 20.8 x 10^-19 J 

E = hc/λ

E = h(λf)/λ = hf                           (  Substitute formula : c = λf   )

f = E/h

Where    E = Energy of Photon in Joules

             h = Plank's constant = 6.626 x10^-34.

             λ = wave length

             c = Speed of light  = 3 x10⁸ m/s.

             f = frequency of a photon in Hz

f = E/h

Substitute : E = 20.8 x 10^-19  , h = 6.626 x10^-34

f = (20.8 x 10^-19)/( 6.626 x10^-34)

f = 3.13915  x 10¹⁵  Hz

The frequency of a photon is 3.13915  x 10¹⁵ Hz.