Final answer:
The stopping potential in the photoelectric effect is determined by the frequency of the incident light, not its intensity, amplitude, or phase. Higher frequency increases the photoelectrons' energy, necessitating a higher stopping potential to halt the current, whereas intensity only affects the number of photoelectrons and hence the photocurrent. The correct answer is option C.
Step-by-step explanation:
The stopping potential in the context of the photoelectric effect is a concept that describes the minimum voltage needed to stop the current of photoelectrons emitted from a metal surface when it is irradiated with light. According to the experimental observations and Einstein's theory of the photoelectric effect, the kinetic energy of the emitted electrons, and hence the stopping potential, depends on the frequency of the incident radiation, not its intensity, amplitude, or phase. This is because each photon's energy is directly proportional to its frequency, which is consistent with the equation E = hf, where h is Planck's constant and f is the frequency of the photon. A higher frequency of incoming light increases the energy of the photoelectrons, which in turn would require a greater stopping potential to halt the current.
Intensity of incident radiation does affect the number of photoelectrons emitted, and thus the magnitude of the photocurrent, but not the stopping potential. The experimental curves that plot photocurrent versus applied potential show that photocurrent reaches a plateau at a certain potential regardless of the light's intensity, but the stopping potential itself remains constant for any given frequency of light.
The presence of a cut-off frequency also illustrates that below a certain frequency, no electrons are emitted, irrespective of the light's intensity. This cut-off frequency is a characteristic property of the material and this phenomenon cannot be explained by classical theories which predict that any frequency of light could cause the ejection of electrons, given sufficient intensity.