In which scenario does the intensity of radiation influence photoelectron emission?

The correct scenario where the intensity of radiation directly influences photoelectron emission is when the intensity increases.

In the photoelectric effect, the intensity of incident light refers to the number of photons striking a surface per unit time. When the intensity of the radiation increases, it means that a greater number of photons are available to interact with the material. This increase in available photons leads to a higher likelihood of interactions that can cause electrons to be emitted from the surface. As a result, more photoelectrons are generated when the intensity of the radiation is increased, provided the energy of the photons is above the threshold needed to liberate electrons from the material.

This understanding aligns with the concept that while the energy of individual photons remains constant, higher intensity translates to more photons impacting the surface, thereby increasing the number of emitted photoelectrons.