Final answer:
Cobalt-60, with a half-life of 5.27 years, is used in food irradiation and cancer treatment, and the amount of Cobalt-60 decreases by half every 5.27 years.
Step-by-step explanation:
The student is asking about the half-life of Cobalt-60 and its use in food irradiation and cancer treatment. Cobalt-60 has a half-life of 5.27 years, which means after this period, only half of the original amount remains due to radioactive decay.
For example, if you start with 60 grams of Cobalt-60, you will have 30 grams remaining after one half-life (5.27 years), 15 grams after two half-lives (10.54 years), and so on. This decay also affects the intensity of the radiation emitted, which is used for sterilizing food and medical equipment, and for treating cancer, where its gamma rays are focused on small areas to target cancer cells.