Half life of Co60 is-

Ans. is 'b' i.e., 5.2 years * Half life of cobalt - 60 is 5.2 years.Cobalt - 60* It is an artifical radioactive cobalt.* It has a half life of 5.2-5.3 years.* It is used as a teletherapy source as well as in brachytherapy.* It decays, emits beta and gamma rays, and has to be replaced at regular intervals of about 4-5 years.* It is produced from cobalt - 59, which is a natural nonradioactive substance.* It decays to produce nickel, which is not radioactive.* It has atomic number - 27.* Its atomic weight is 58.93