The photoelectric effect experiment involves the observation of light interacting with a metal surface, resulting in the emission of electrons. This phenomenon was first investigated by Heinrich Hertz in the late 19th century. Hertz discovered that when light with certain frequencies, typically in the ultraviolet range, was incident on a metal surface, it caused the ejection of electrons from the surface.

To carry out this experiment, a vacuum tube is utilized, which contains a cathode made of the metal to be studied and an anode. The cathode is illuminated with monochromatic light of varying frequencies, while the anode is charged with a positive potential. The emitted electrons are then attracted towards the anode and a current can be measured. The intensity of this current provides valuable information about the photoelectric effect.

One crucial observation from this experiment is that the kinetic energy of the emitted electrons depends on the frequency of the incident light, rather than its intensity. This implies that the energy of electrons is determined by the frequency of light and not by the number of photons.

Another important finding is that there is a minimum threshold frequency for the incident light, below which no electrons are emitted. This threshold frequency corresponds to the energy needed to overcome the attractive forces that exist between the metal atoms and the bound electrons. Light with frequencies below this threshold does not possess enough energy to free the electrons, regardless of its intensity.