What is the primary means of protection against alpha radiation?

• A. Lead shielding
• B. Plastic barriers
• C. A sheet of paper or the outer layer of skin
• D. Glass enclosures

Answer: (C)

The primary means of protection against alpha radiation is a sheet of paper or the outer layer of skin because alpha particles are relatively large and carry a positive charge, making them less penetrating compared to other types of radiation, such as beta or gamma rays. Alpha particles can be stopped by very thin materials, which is why common items like paper and human skin are sufficient for protection.

Alpha radiation has low penetration power, meaning that it can be effectively blocked by materials as thin as a few micrometers, such as the outer layer of the skin. This property makes alpha radiation relatively safe when the source is external; however, if alpha-emitting materials are ingested or inhaled, they can pose a significant health risk because they are then in close proximity to living tissues.

While other options, such as lead shielding, provide protection against different types of radiation, they are unnecessary for alpha radiation due to its limited penetrating ability. Plastic barriers and glass enclosures also do not provide any additional advantage for alpha particles, given that even very light and thin materials are sufficient to prevent their harmful effects.