The unit of radioactivity is

The unit of radioactivity is

• A. Becquerel
• B. Grayt
• C. Sievert
• D. Graya

Answer: (A)

Understanding radioactivity involves looking at how fast unstable nuclei decay. That rate is measured with the becquerel, defined as one disintegration per second. So if a source has an activity of 1 Bq, one nucleus decays each second on average. The Gray measures energy deposited in tissue (absorbed dose), not the rate of decay; the Sievert accounts for biological effect (equivalent dose). Spelling variants like “Grayt” or “Graya” aren’t correct units. Therefore, the correct unit for radioactivity is the becquerel.

Understanding radioactivity involves looking at how fast unstable nuclei decay. That rate is measured with the becquerel, defined as one disintegration per second. So if a source has an activity of 1 Bq, one nucleus decays each second on average. The Gray measures energy deposited in tissue (absorbed dose), not the rate of decay; the Sievert accounts for biological effect (equivalent dose). Spelling variants like “Grayt” or “Graya” aren’t correct units. Therefore, the correct unit for radioactivity is the becquerel.