Radiation Safety Practice Exam

Which type of radiation is NOT primarily an external hazard?

1. X-rays

2. Alpha radiation

3. Gamma radiation

4. Beta radiation

The correct answer is: Alpha radiation

Alpha radiation is considered distinct in terms of its hazard profile. Unlike X-rays, gamma radiation, and beta radiation, which can penetrate the body and are of concern from external exposure, alpha particles are relatively large and carry a positive charge. They have low penetration power and cannot pass through human skin. When alpha-emitting materials are ingested or inhaled, they become significant internal hazards, as they can damage tissues directly within the body. This internal exposure can lead to more severe biological effects compared to external exposure, due to the concentrated energy deposition in a localized area, such as lung tissue or gastrointestinal lining. Therefore, while other types of radiation primarily pose external threats due to their penetrating capabilities, alpha radiation is uniquely recognized for its potential harm when internalized, making it the correct answer for this question.