What does the term "half-life" describe in the context of radiation?

The term "half-life" specifically refers to the time required for half of the quantity of a radioactive substance to undergo decay. This concept is fundamental in understanding how radioactive isotopes behave over time. Each radioactive isotope has a unique half-life, which can range from fractions of a second to millions of years, depending on the stability of the isotope.

Understanding half-life is crucial in various fields, such as medicine, nuclear energy, and radiological safety, because it helps predict the rate at which a radioactive material will diminish over time, which impacts decisions related to safety, waste management, and treatment protocols in medical applications.

Options that describe the time for a substance to double or the stabilization of radiation levels do not accurately capture the essence of half-life. Similarly, duration of exposure pertains to a different aspect of radiation safety and does not relate to the decay process inherent in the concept of half-life. Thus, the definition that aligns with half-life is that it describes the time taken for half of a radioactive substance to decay.