The decay constant for the radioactive nuclide `64Cu` is `1.516 xx 10^(-5) s^(-1)` . Find the activity of a sample containing `1mug` of `64Cu`. Atomic weight of copper = 63.5 g mole^ (-1). Neglect the mass difference between the given radioisotope and normal copper.

Explanation

`63.5 g` of copper has `6xx10^(23)` atoms. Thus, the number of atoms in `1 mu g` of `Cu` is
`N=(6xx10^(23)xx1 mu g)/(63.5 g)=9.45xx10^(15)`
Thus acitvity `=lambdaN`
`=(1.516xx10^(-5)s^(-1))xx(9.45xx10^(15))=1,43xx10^(11)"disintegration"//s`
`=(1.43xx10^(11))/(3.7xx10^(10))Ci=3.86 Ci`
Activity after `n` half lives : `(A_(0))/(2^(n))`