Which type of particles are described as least harmful and can be blocked by fabric?

Alpha particles are relatively large and carry a positive charge, which means they are less penetrating than other types of radiation. Because of their size and charge, they can be easily stopped by materials such as a sheet of paper or even the outer layers of human skin. In fact, a fabric can effectively block alpha particles due to their limited ability to penetrate solid materials.

This characteristic makes alpha radiation the least harmful when it comes to external exposure, although it can be dangerous if alpha-emitting materials are ingested or inhaled. Understanding the behavior of alpha particles is essential in assessing risks associated with radioactive materials and implementing appropriate safety measures.