The maximum kinetic energy of emitted photoelectrons depends on

In photoelectric effect, the maximum kinetic energy of emitted photoelectrons depends on the frequency of incident radiation. We have $K E=h v-\phi$ Where $\phi$ is work function, which is the minimum energy required to remove electrons from the metal plate; $f$ is frequency of incident radiation; h is Planck's constant. Therefore, $(K E)_{\max } \propto f$.