Which type of radiation can be stopped by several feet of concrete or several inches of lead?

Gamma radiation is a highly penetrating form of electromagnetic radiation that results from nuclear decay. It possesses high energy and a short wavelength, which allows it to pass through most materials with ease. To effectively shield against gamma radiation, dense materials like lead or thick barriers such as several feet of concrete are required. This is due to the fact that gamma photons do not have mass and charge, enabling them to easily traverse normal matter.

In contrast, alpha radiation consists of helium nuclei and can be stopped by a sheet of paper or even the outer layer of human skin, while beta radiation, which consists of electrons or positrons, can usually be blocked by materials like plastic or glass. X-ray radiation, while also penetrating, does not require nearly as thick barriers as gamma radiation, making a comparison of shielding effectiveness between them essential in understanding radiation protection.