Question

A photon of wavelength 4 x 10⁻⁷ m strikes on metal surface, the work function of the metal being 2.13 eV. Calculate: the energy of the photon (eV) (1 ev= 1.6020 x 10⁻¹⁹J).

Answer 1

Energy (E) of a photon =  

Here, h is the plank’s constant =6.626 X 10-34 Js

          C is the velocity of light in vacuum = 3 X 108 ms-1

            Is the wavelength of photon =4 X 10-7 m

Putting the values in the relation E, we get

 

E =4.9695 X 10-19 J

Therefore, Energy of the photon is 4.97 X 10-19 J.