What is the approximate half-life of Cobalt 57?

Cobalt-57 has a half-life of approximately 271.8 days, which is about 9 months. This measurement indicates the time it takes for half of the radioactive isotope to decay into a more stable form. Understanding the half-life is critical in fields such as health physics and radiochemistry, especially in applications related to diagnostics and treatment in medicine. The significance of knowing Cobalt-57's half-life comes into play when considering how long the isotope remains radioactive and potentially hazardous in various settings, including clinical environments, research laboratories, and industrial applications.

In this context, the option that states 9 months aligns closely with the established half-life of Cobalt-57, making it the most accurate choice among the options presented. This knowledge is essential for professionals working with radioactive materials, as it helps them assess safety protocols and manage exposure risk effectively.