Radiation of wavelength 300   nm and intensity 100   W   m - 2 falls on the surface of a photosensitive material. If 2 % of the incident photons produce photo electron, the number of photoelectrons emitted from an area of 2   cm 2 of the surface is nearly

Step-by-step solution

Power of radiation is expressed as, Power = N hc λ Here, N   is the number of photons per unit time per unit area. ⇒ P = N hc λ ⇒ N = P λ hc = 100   W   m - 2 × 300 × 10 - 9   m 6 . 6 × 10 - 34   J   s × 3 × 10 8   m   s - 1 = 1 . 51 × 10 20   m - 2   s - 1 Given that 2 %   of the incident, photons produce photoelectron therefore, number of photoelectrons produced by photons is = 2 100 × 1 . 51 &#215