Final answer:
The latent image on a photographic film is created by energy transfer during exposure, which involves a chemical change in the film's emulsion when it is struck by ionizing radiation.
Step-by-step explanation:
The latent image is created by energy transfer during exposure. This exposure can be due to various forms of energy, such as ionizing radiation, which includes alpha particles, beta particles, or photons. When a quantum of energy from a radioactive particle interacts with the photographic emulsion, it alters it chemically, thus creating a chemical change that forms the latent image on the film. This process of film exposure through ionizing radiation is not entirely efficient, however; not all incident radiation will interact with the emulsion, and not all interactions will produce the necessary chemical change to create the visible image once developed.