Radioactive contamination is typically measured in disintegration per minute (dpm) or counts per minute (cpm). Which of the following statements is true?

Radioactive contamination is typically measured in disintegration per minute (dpm) or counts per minute (cpm). Which of the following statements is true?

• A. Disintegration per minute (dpm) or counts per minute (cpm)
• B. Grams per cubic meter
• C. Sieverts
• D. Curies

Answer: (A)

Radioactive contamination is quantified by how fast radioactive decays are detected from a contaminated area or item. This is expressed as disintegration per minute (dpm) or, when using a detector, counts per minute (cpm). dpm is the true decay rate of the contaminant present, while cpm is the detector’s reading of that rate, which can vary with instrument efficiency and setup. These units directly measure the contamination level you’re trying to control or decontaminate. Grams per cubic meter would describe a mass concentration, not radioactivity. Sieverts measure dose to a person, not how much contamination is present on a surface. Curies are another way to express activity, but they’re larger units and less practical for routine contamination monitoring, where dpm or cpm provide a more immediate and actionable readout.

Radioactive contamination is quantified by how fast radioactive decays are detected from a contaminated area or item. This is expressed as disintegration per minute (dpm) or, when using a detector, counts per minute (cpm). dpm is the true decay rate of the contaminant present, while cpm is the detector’s reading of that rate, which can vary with instrument efficiency and setup. These units directly measure the contamination level you’re trying to control or decontaminate.

Grams per cubic meter would describe a mass concentration, not radioactivity. Sieverts measure dose to a person, not how much contamination is present on a surface. Curies are another way to express activity, but they’re larger units and less practical for routine contamination monitoring, where dpm or cpm provide a more immediate and actionable readout.