In the context of the photoelectric effect, what is the purpose of the stopping voltage?

The stopping voltage in the context of the photoelectric effect refers to the voltage applied in such a way as to reduce the energy of the emitted photoelectrons. Its primary function is to create an electric field that can counteract the kinetic energy of the photoelectrons. When a photoelectron is emitted, it increases in kinetic energy due to its interaction with light. By applying a stopping voltage, you effectively create a potential barrier that can prevent the most energetic photoelectrons from reaching the detector.

This is crucial for understanding the operation of photoelectric experiments, where measuring the maximum kinetic energy of photoelectrons is important. By adjusting the stopping voltage, one can determine the work function of the material and gain insights into the energy levels involved in electron emission. Thus, the stopping voltage serves to selectively filter out higher-energy electrons, allowing for an analysis focused on the lower-energy emissions while establishing a clear relationship between the frequency of the incident light and the energy of the emitted electrons.