Abstract
The photoelectric effect occurs when light of a sufficiently high frequency strikes a surface, exciting the electrons on that surface to the point that they are ejected from it. Those ejected electrons are called photoelectrons, which can be collected and sent through a circuit. By measuring the resulting current and the negative voltage required to stop it at various frequencies and intensities, some essential relationships can be established. The first is the relationship between stopping voltage and frequency. This relationship is linear, and using its slope, Planck’s constant was estimated to be 6.5(2) \(\times\) 10\(^{-34}\) Js. The second relationship is between the stopping voltage and intensity. Classical wave theory predicts that an increase in intensity should increase the stopping voltage. In reality, the data shows that the two are entirely unrelated. This result directly contradicts wave theory, supporting theories of light’s particle-like behavior and the existence of photons.
