How does the maximum kinetic energy of electrons emitted vary with the work function of the metal??

Hi,

Let a monochromatic light of frequency ν be incident on the surface of a metal of work function Ø. The energy of a photon in the light is, E = hν. When a photon strikes a free electron the surface of the metal, the electron gets an extra energy E = hν and may come out of the metal. The electron trying to escape the surface will be attracted by the surface with a force equal to Ø. So, the maximum KE of the electron is given by,

Since, for a monochromatic light hν is a constant. The graph for KE versus Ø is a straight line with a negative slope.

The graph signifies the dependence of KE of an emitted electron on the work function of the metal.