During the nuclear explosion, one of the products is 90 S r with half life of 6.93 years. If 1 μ g of 90 S r was absorbed in the bones of a newly born baby in place of C a , how much time, in years, is required to reduce it by 90 % if it is not lost metabolically ____________.

Step-by-step solution

Radioactive disintegration is always a first order reaction for a first order reaction. Radioactive decay is the process by which an unstable atomic nucleus loses energy by radiation. K t = 2.303     log A o A t where A o = initial concentration A t = concentration at time ‘t’ t 1 2 = 0.693 K K = 0.693 t 1 2 = 0.693 6.93 ⇒ 0.1   y e n t s − 1 t 90 % = 2.303 0.1 log 100 10 t 90 % = 23.03 years.