Radioactivity refers to the rate at which a particular nuclide undergoes radioactive decay. Which of the following units is used to measure radioactivity?

The correct answer is Curie.

Key Points

• Curie (Ci) is a unit used to measure radioactivity, named after Marie and Pierre Curie.
• One Curie corresponds to 3.7 × 10¹⁰ disintegrations per second, representing the decay rate of radioactive isotopes.
• It is primarily used in fields such as nuclear medicine, radiology, and environmental monitoring.
• The Curie is considered a large unit, and smaller units such as millicurie (mCi) or microcurie (μCi) are often used in practice.
• The International System of Units (SI) uses the Becquerel (Bq) for measuring radioactivity, where 1 Curie = 3.7 × 10¹⁰ Becquerels.

Additional Information

• Radioactivity: It is the phenomenon of spontaneous emission of particles or electromagnetic radiation from the nucleus of unstable atoms.
• Roentgen (R): It is a unit of exposure used to measure ionizing radiation, particularly in air, but does not measure the decay rate.
• Becquerel (Bq): The SI unit for radioactivity, defined as one disintegration per second.
• Applications of Radioactivity: Used in medical imaging (e.g., PET scans), cancer treatment (radiotherapy), energy generation (nuclear power), and archaeological dating (carbon dating).
• Safety Measures: Handling radioactive materials requires protective equipment, proper shielding, and adherence to radiation exposure limits to minimize health risks.