Final answer:
The primary requirement for light production involving electrons is energy absorption, which can lead to the excitation of electrons and, in certain processes like photosynthesis or the photoelectric effect, the production of light or ejection of electrons.
Step-by-step explanation:
The primary requirement for light production involving electrons is energy absorption. When electrons absorb energy, they can be excited to higher energy levels. For instance, in photosynthetic organisms, chlorophyll molecules within the photosystems absorb light and become excited. This excitation energy is then transferred to the primary electron acceptor, which uses the energy to excite electrons resulting from the splitting of water. In the context of the photoelectric effect, as described by Einstein, an increase in light intensity means more photons are available, which can then lead to the ejection of electrons if the photons have enough energy.