How is ionizing radiation classified?

Ionizing radiation is classified as either particulate or electromagnetic radiation, which is the correct classification. Particulate radiation includes particles such as alpha particles, beta particles, and neutrons that have mass and charge, and they can directly affect atoms in the materials they pass through. On the other hand, electromagnetic radiation includes forms such as X-rays and gamma rays, which have no mass and carry energy in wave form.

This classification is essential for understanding the different interactions that these types of radiation have with matter. For instance, particulate radiation tends to have more direct physical interactions and can cause ionization in the atoms they collide with more effectively than electromagnetic radiation, due to their mass and charge.

Other forms of classification mentioned in the options, like those based solely on frequency or source, do not encompass the full scope of how ionizing radiation operates or its behaviour in different contexts. Hence, the classification into particulate and electromagnetic categories provides a more comprehensive understanding of ionizing radiation and its implications in fields such as dental radiography and radiation safety.