What is a Curie (Ci) used to measure?

A Curie (Ci) is a unit of measurement that quantifies the activity of radioactive material. Specifically, it is defined based on the number of disintegrations occurring per second in a sample of radioactive material. One Curie is equivalent to 3.7 x 10^10 disintegrations per second, which illustrates the intensity of radioactivity present in the material.

This measurement is critical in fields such as nuclear physics, medicine, and environmental science, where understanding the level of radioactivity is essential for safety and health assessments. In these contexts, knowing the activity of radioactive substances helps in evaluating exposure risks and implementing necessary safety measures.

The other measurements mentioned, such as air quality, water toxicity, and the weight of hazardous materials, pertain to different areas and utilize different measurement units not related to radioactivity. Therefore, they do not align with the specific definition of a Curie.