Which type of radiation can be stopped with just a piece of paper?

• A. Beta radiation
• B. Gamma radiation
• C. Alpha radiation
• D. X-ray radiation

Answer: (C)

Alpha radiation can be stopped by a piece of paper because it consists of relatively large particles made up of two protons and two neutrons, which is essentially the nucleus of a helium atom. Due to their mass and charge, alpha particles have a very low penetration power. They can be easily absorbed by even a few centimeters of air or a thin barrier such as paper.

In contrast, beta radiation, which consists of fast-moving electrons, can penetrate further and requires a denser material for shielding. Gamma radiation and X-ray radiation, both forms of electromagnetic radiation, have even greater penetration abilities and cannot be effectively shielded by something as thin as paper; they typically require dense materials like lead or several centimeters of concrete for adequate protection. Understanding the characteristics of these radiation types is essential for effective radiation safety practices.