Which type of radiation is most penetrating?

Gamma rays are the most penetrating type of radiation among the options provided. This is primarily due to their nature as electromagnetic waves, which possess high energy and short wavelengths. Unlike alpha and beta particles, which are charged and interact more readily with matter, gamma rays are uncharged. This characteristic allows them to pass through materials, including human tissue, lead, and concrete, with relative ease.

In practical terms, while alpha particles can be stopped by a sheet of paper or even the outer layer of human skin, and beta particles can be blocked by a few millimeters of plastic or glass, gamma rays require much denser materials for effective shielding. Thus, when considering radiation protection, understanding the penetrative abilities of gamma rays is crucial for assessing the risks associated with exposure and determining the appropriate protective measures.