Which of the following materials can shield alpha radiation?

Alpha radiation consists of helium nuclei, which are relatively heavy and carry a positive charge. Due to their mass and charge, alpha particles have a very short range and cannot penetrate deeply into materials. They can be effectively stopped by very lightweight materials.

Materials like a piece of paper or lightweight clothing are sufficient to shield against alpha particles because they can stop the particles before they can reach the skin or enter the body. This highlights the fact that alpha radiation does not require heavy shielding materials to be contained, as even a simple barrier can be effective.

In contrast, some of the other materials mentioned, such as lead, steel, water, and concrete, while effective against heavier and more penetrating forms of radiation like gamma rays or beta particles, are not necessary for alpha radiation. In fact, using heavier materials is an over-commitment for shielding against a type of radiation that can easily be blocked by much lighter substances. This emphasizes the unique characteristics of alpha radiation and the importance of using appropriate materials for specific types of radiation protection.