The specific activity of a preparation consisting of radioactive `Co^(58)` and non-radioactive `Co^(59)` is equal to `2.2xx10^(12)` disintergration per sec gram. The half-life of `Co^(58)` os `71.3` days. The ratio of the mass of radioactive cobalt in that prepartaion to the total mass of the prepartion in percentage is

Options

A. `2.1%`
B. `99%`
C. `0.1818%`
D. `97.9%`

Answer

C

Explanation

Cobalt preparation `=Co^(58)+Co^(59)`
Here `Co^(58)` is radioactive `Co^(59)` is non-radioactive Activity means, it is only for `Co^(58)` specific activity measured for total preparation. Specific activity of cobalt preparation `=2.210^(12)dis.sec^(-1).gm^(-1)=N lambda`
`("mass of" C^(58))/("total mass of cobalt preparation")=("aboveresult")/(1 gm)xx100%`