question_answer 9)

Obtain the amount of necessary to provide a radioactive source of 8-0 mCi strength. The half-life of  is 5.3 years.  

Answer:

1 Ci = 3-7 x 1010 disintegrations per second. = 2.96 x 108 disintegrations/s. Also,      T = 5.3 years = 5.3 x 365 x 24 x 60 x 60s = 1.67 x 108s Now usingor                 Now 6.023 x 1023 atoms of cobalt have mass = 60 g 7.13 x 1016 atoms of cobalt have mass