In radiation exposure terms, which unit is commonly used to express dose?

• A. Rem or millirem
• B. Curies
• C. Sieverts
• D. Becquerels

Answer: (A)

When talking about how much radiation exposure a person actually receives, we use a dose-equivalent unit that reflects the biological impact, not just the amount of radiation present. Rem, and its smaller unit millirem, are built to express that dose in terms of potential effect on human tissue. This makes rem/millirem the commonly used units in many radiation safety contexts, especially in traditional or occupational settings.

Curies and becquerels measure activity—the rate at which a material is decaying—not how much energy is absorbed by the body. Sieverts are the SI version of dose equivalent and serve the same purpose as rem, but in many training materials rem is the familiar unit for expressing dose in everyday practice.