Half life of cobalt-60: September 2011
Ans. C: 5.3 years Half life of cobalt-60 is 5.3 years, therefore in practice have to replaced every 3-4 years Half-lives of impoant isotopes: 1-131: 8 days Rn 222: 3-6 days Co 60: 5.2 years
3.3 years
4.3 years
5.3 years
6.3 years