Radiation Safety Practice Exam

Which unit of measurement is used for very small quantities of radioactivity?

1. Ci

2. mCi

3. µCi

4. nCi

The correct answer is: µCi

The unit of measurement used for very small quantities of radioactivity is the microcurie, which is represented as µCi. This unit is part of the curie family of measurements, where one curie (Ci) is a significantly larger quantity, equal to 3.7 x 10^10 disintegrations per second. When dealing with small amounts of radioactivity, scaling down from the curie is essential for practical applications and safety. The milliCurie (mCi) represents one-thousandth of a curie, while the microcurie represents one-millionth of a curie. The nanocurie (nCi) is even smaller, representing one-billionth of a curie. The microcurie is particularly useful in medical applications and research where precise measurements of low levels of radiation are required to ensure safety and appropriateness of interventions. In terms of common usage, the microcurie provides a convenient middle ground for measuring small amounts of radioactive materials, making it particularly relevant for contexts such as radiological imaging and small-scale laboratory experiments. This understanding of measurement scales is crucial for professionals working in radiation safety, ensuring they can effectively communicate and manage the risks associated with varying levels of radioactivity.