What are the three steps recommended to protect oneself against the effects of radioactive materials?

The correct choice highlights the foundational principles of radiation safety: time, distance, and shielding.

Time refers to minimizing the duration of exposure to radioactive sources. The less time spent near radiation, the lower the dose received, thus reducing the potential for health risks associated with exposure.

Distance is the second key principle; increasing the distance from a radioactive source significantly reduces exposure. Radiation intensity decreases with distance due to the inverse square law, meaning that even small increases in distance can lead to a substantial decrease in exposure.

Shielding involves using physical barriers to protect against radiation. Different types of radiation require different materials for effective shielding, such as lead for gamma radiation or concrete for beta particles. Proper shielding can dramatically reduce radiation levels and protect individuals in contaminated environments.

These three steps are essential for effectively mitigating the risks associated with radioactive materials.