Final answer:
The rule that applies to the principle of radiation safety is ALARA. It suggests minimizing radiation exposure by reducing the time spent exposed, increasing distance from the source, and using appropriate shielding. Specifically, gamma rays require dense materials for protection, while alpha particles are best shielded by avoiding inhalation or ingestion.
Step-by-step explanation:
The rule that applies to the principle of radiation safety is ALARA, which stands for "As Low As Reasonably Achievable." This principle embodies the idea that all exposure to radiation should be minimized to the lowest levels possible, behind practical considerations. To comply with ALARA, you should follow these radiation protection measures:
- Keep the minimum possible time in the radiation environment - less the time means less exposure.
- Keep as much distance from the radiation source as possible - the radiation intensity drops inversely proportional to the square of the distance.
- Keep shielding between you and the source of radiation as much as possible - the more the shielding the less the exposure.
Protecting Against Alpha Particles and Gamma Rays
Gamma rays penetrate matter more deeply than alpha particles. Protective measures against gamma rays include using dense materials like lead for shielding. In contrast, alpha particles can often be blocked by a sheet of paper or the outer layer of the human skin, so they are a greater threat when inhaled or ingested. Thus, for protection against alpha-emitting substances, do not inhale radioactive dust and ensure proper containment of the substances.