Which type of radiation is easily stopped by thin materials such as paper and clothing?

• A. Alpha
• B. Gamma
• C. Beta
• D. Neutron

Answer: (A)

The key idea is how different types of radiation interact with matter and how shielding works for each. Alpha particles are large, positively charged helium nuclei that interact very strongly with atoms, so they lose energy quickly and travel only a short distance in air or through thin materials. That means a simple sheet of paper or a few layers of clothing can stop them. In contrast, beta particles are more penetrating and require thicker or denser shielding, like a few millimeters of plastic or aluminum. Gamma rays are photons with no mass or charge and can pass through many materials, needing dense shielding such as lead or concrete. Neutrons, being uncharged, are slowed and captured best by materials rich in light elements like hydrogen. So the type easily stopped by thin materials such as paper and clothing is alpha radiation because of its strong interactions and short range in matter.