Photo electric effect

In an experiment of photo-electric effect, the graph of maximum kinetic energy E_(k) of the emitted photoelectrons versus the frequency v of the incident light is a straight line AB as shown in figure below : Work function of the metal.

In an experiment of photo-electric effect, the graph of maximum kinetic energy E_(k) of the emitted photoelectrons versus the frequency v of the incident light is a straight line AB as shown in figure below : Threshold frequency of the metal.