The photoelectric effect is a phenomenon that occurs when light, usually in the form of photons, strikes a material surface and liberates electrons from their atoms. To study this effect, a typical experimental setup consists of a vacuum chamber equipped with a light source, a metal plate known as the photocathode, and an electron collector called the anode.

When light of a sufficiently high frequency or energy is directed towards the photocathode, it emits electrons. These emitted electrons are then accelerated towards the anode by applying a potential difference across the two electrodes. The resulting current can be measured to understand the characteristics of the photoelectric effect.

One important observation made during these experiments is that the number of emitted electrons is directly proportional to the intensity of incident light. Greater intensity results in more electrons being emitted, provided the light frequency exceeds the threshold frequency for that particular material. The threshold frequency is the minimum frequency below which the photoelectric effect does not occur, irrespective of light intensity.

Furthermore, experiments have shown that the kinetic energy of the emitted electrons is independent of light intensity but depends solely on the frequency of incident light. This observation supports the particle-like nature of light and implies that the energy transfer between photons and electrons is quantized.