Texas Industrial Radiography Gamma Practice Test

What does the unit "Rem" measure in radiation contexts?

1. Activity

2. Dose in air

3. Dose in man

4. Intensity

The correct answer is: Dose in man

The unit "Rem" is a measure of dose equivalent in radiation contexts, specifically indicating the biological effect of radiation on human tissue. It accounts for the type of radiation and its potential to cause harm, making it especially relevant in protecting human health from radiation exposure. The Rem is used to quantify the amount of energy absorbed by tissue and to evaluate the risk of radiation-related health effects, which is why the correct answer highlights its association with the dose in humans. In contrast, activity pertains to the rate of radioactive decay and is measured in units like the Curie or Becquerel, which do not consider biological effects. Dose in air typically refers to the exposure of air to radiation without factoring in biological impact on tissue, which is distinct from the human focus of the Rem. Intensity measures the strength of radiation in a certain area, but again does not take into account the biological effects on living organisms. Thus, the Rem serves a critical role in assessing potential risks to human health from radiation exposure.