What type of radiation is considered the least dangerous if external but very dangerous if ingested or inhaled?

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

Answer: (C)

Alpha radiation is indeed considered the least dangerous when it comes to external exposure because alpha particles have relatively low penetration power. They can be stopped by a sheet of paper or even the outer layer of human skin, which means that they do not pose a significant risk as long as the source of radiation is outside the body.

However, alpha particles become very hazardous when ingested or inhaled. Once inside the body, they can interact with biological tissues and cells at a very close range, resulting in significantly greater biological damage compared to other types of radiation. This is due to their charge and mass, which allows them to cause more ionization and cellular damage in a localized area, increasing the potential for serious health effects, including cancer.

In contrast, other types of radiation—including beta, gamma, and neutron radiation—have different properties and risks associated with external exposure and internal contamination. Understanding the nature of alpha radiation is crucial for handling hazardous materials safely and protecting oneself from potential exposure.