Radiation Safety Practice Exam

What does the roentgen measure the ionization of?

1. Water by gamma rays

2. Air by gamma rays or X-rays

3. Soil by alpha particles

4. Metal by beta particles

The correct answer is: Air by gamma rays or X-rays

The roentgen is a unit of measurement that specifically quantifies the amount of ionization produced in air by gamma rays or X-rays. When gamma rays or X-rays pass through air, they can ionize the air molecules, resulting in a measurable amount of charged particles. This measurement is significant for radiation safety because it helps assess exposure levels in environments where ionizing radiation is present. In the context of radiation protection and safety, understanding how much ionization occurs in the air is crucial, as it directly relates to potential biological effects on human health. The focus on air is important because most radiation detection and exposure assessments are conducted in the atmosphere surrounding individuals. The other options provided do not align with the definition and application of the roentgen. For example, measuring ionization in water, soil, or metal involves different units and contexts that are not applicable to the roentgen as it applies specifically to air.