Which principle is key to radiation protection?

The principle of Time, Distance, and Shielding is fundamental to radiation protection because it helps minimize exposure to radiation, thereby reducing potential harm to individuals working in environments where radiation is present.

Time refers to the duration of exposure; the less time spent near a radioactive source, the lower the dose received. Distance emphasizes maintaining as much physical distance as possible from the radiation source since radiation intensity decreases with increasing distance. Shielding involves using materials that can absorb or block radiation, effectively protecting individuals from harmful exposure.

These three components work synergistically to enhance safety and mitigate risks associated with radiation in various settings, particularly in nuclear facilities. The other choices—energy, matter, and motion; speed, temperature, and pressure; and volume, density, and mass—do not directly relate to radiation protection principles and thus do not form a basis for minimizing radiation exposure.