The half-life of radium is 1600 years. After how many years will one gram of the pure radium be reduced to one centigram?

Explanation

`N_(0)/N=2^(t//T`
`1/10^(-2)=2^(t//1600)`
(or) `10^(2)=2^(t//1600)`
(or) `2log_(10)10=t/1600log_(10)2`
(or) `t=(2xx1600)/(log_(e)2)=(3200)/(0.3010)=10631.2`years.