What does the maximum kinetic energy (or the maximum speed) of a photoelectron depend on ?

Maximum kinetic energy of photoelectron depends on

Calculate the maximum kinetic energy and maximum velocity of the photoelectrons emitted when the stopping potential is 81V for the photoelectric emission experiment.

The maximum kinetic energy of photoelectrons

Assertion : All the photoelectrons emitted from the matal do not have the same energy. Reason : The maximum kinetic energy of photoelectrons depends on the light soures and the emitted plate material.