What type of radiation can be stopped by a sheet of paper?

Alpha particles, which are positively charged particles consisting of two protons and two neutrons, can be effectively stopped by a very thin barrier, such as a sheet of paper. This is because alpha particles have a low penetration ability due to their relatively large mass and charge, which means they interact strongly with matter.

When alpha particles encounter the atoms in the paper, they lose energy as they collide with electrons and other components of the paper, resulting in their absorption before they can penetrate further. This characteristic makes alpha radiation less hazardous when external to the human body, although it can be quite dangerous if alpha-emitting materials are ingested or inhaled.

In contrast, beta particles, gamma rays, and X-rays have greater penetration capabilities due to their different physical properties and require denser materials for effective shielding. Beta particles can be stopped by materials such as plastic or glass, while gamma rays and X-rays need much thicker, denser barriers, like lead or concrete, to reduce their intensity significantly. This understanding of alpha particles’ limitations is crucial for radiation safety and shielding practices.