The half life of a cobalt radio istope is 5.3 years. What strength will a milli curic source of isotope have after a period of one year?

Options

A. 0.10 mci
B. 1.21 mci
C. 0.87 mci
D. 0.78 mci

Answer

C

Explanation

`lambda N_(0)=R=1 and lambda N=R.`
`N/N_(0) =R. =e^(-lambda//t) or log_(10) (N)/(N_(0)) =(lambda t)/(2.3026)`
`or log_(10) (1/R.)=(0.693 xx t)/(2.3026 xx T)=(0.693 xx 1)/(203026 xx 5.3) [lambda=(0693)/(T)]`
`or 1/(R.)=1.14 therefore R.=(1)/(1.14) =0.87 m Ci`