What are the two main categories of radiation sources?

The two main categories of radiation sources are natural and artificial sources. Natural sources include radiation that occurs naturally in the environment, such as cosmic rays, radon gas, and terrestrial radiation from soil and rocks. These sources are part of our surroundings and contribute to background radiation, which individuals are exposed to on a daily basis.

Artificial sources, on the other hand, refer to radiation that is produced by human activities. This includes medical procedures (like X-rays and radiation therapy), nuclear power generation, and exposure from industrial applications. Understanding the distinction between these two categories is crucial for radiation safety, as it informs risk assessment and development of safety practices to minimize exposure to harmful radiation levels.

Other options, while they may involve relevant concepts in understanding various aspects of radiation, do not capture the primary classification of radiation sources as effectively as the natural and artificial categorization does.