Which of the following defines photoemission?

Photoemission refers to the process where electrons are emitted from a material as a result of absorbing light, typically ultraviolet or visible light. This phenomenon occurs when photons strike a material's surface, imparting enough energy to overcome the work function of the material, which is the minimum energy needed to release an electron from that material.

In this context, the focus is on how light interacts with a material to cause electron ejection, which is foundational in areas such as photodetectors, photoelectric cells, and other electronic components that rely on light-to-electricity conversion. The other options involve different particles or stimuli that are not related to the principle of photoemission, affirming the specificity of the correct definition related to electrons and light interaction.