Abstract:  In the photoelectric effect experiment, the saturation photocurrent is affected by many factors, including the voltage between the plates, the frequency of the incident light, the intensity of the incident light and the photoelectric efficiency of the cathode material. In order to explore the influence of these factors on saturated photocurrent, we use the control variable experiment method. The experimental results show that the incident light intensity has a linear relationship with the saturation photocurrent until the saturation photocurrent is reached at a certain photoelectric efficiency and frequency. When the incident light frequency and light intensity are fixed, the photoelectric efficiency of the cathode material will be affected when the voltage between the plates is not large enough, and the saturation photocurrent will be affected. When the light intensity and voltage are fixed, the number of photons is different for different frequencies of light, and the saturation photocurrent is directly related to the number of photons. In addition, the photoelectric efficiency of the cathode material is nonlinear with the frequency of the incident light, resulting in a nonlinear relationship between the frequency of the incident light and the saturated photocurrent. To sum up, the saturated photocurrent is the limit value under a specific condition, which is the result of multiple factors.

Key words: photoelectric effect, saturation photocurrent, incident distance, incident light intensity, incident light frequency