Monday, 25 April 2016

Laws of photoelectric emission

Laws  of  photoelectric  emission

The experimental observations on photoelectric effect may be summarized  as follows,which  are  known as the fundamental laws of photoelectric emission.

  • There is a minimum frequency called the threshold frequency, for a given photo sensitive  material,below which emission of photoelectrons stops completely.
  • For a given photosensitive material,the photo electric current is directly proportional to the intensity of the incident radiation,provided the frequency is greater than the threshold  frequency.
  • The photoelectric emission is an instantaneous process. i.e. there is no time lag between the incidence of radiation and the emission of  photo electrons.
  • The maximum kinetic energy of the photo electrons is directly proportional to the frequency of incident radiation,but is independent of  its intensity.