Which of the following best defines characteristic radiation?

Characteristic radiation is specifically produced when a high-energy electron collides with an inner shell electron (commonly a k-shell electron) in a target atom, causing the inner shell electron to be ejected. This vacancy is then filled by an electron from a higher energy level within the atom. As the higher-energy electron transitions to the lower energy state, it releases energy in the form of electromagnetic radiation, which is what we refer to as characteristic radiation.

This mechanism is crucial in X-ray production, as the specific energies of the emitted radiation correspond to the differences in energy levels of the electrons in the atom. Each element emits characteristic radiation at distinct energy levels, thereby creating a unique spectral signature that can be identified and utilized in various imaging applications and analyses.

The other options do not accurately describe characteristic radiation. For instance, radiation resulting from interactions with outer shell electrons refers to different types of radiation, such as Bremsstrahlung radiation, which involves interactions that do not lead to photoelectron emission but rather a broad spectrum of energies. The statement about radiation emitted when electrons change energy levels is too general and does not specify the inner shell transitions that lead to characteristic radiation. Lastly, the notion of non-ionizing radiation applies to different radiation types and is not applicable