Question

How many half-lives have passed when there are three times as much daughter isotope as parent isotope?

Answer 1

3 half live have passed.

Step-by-step explanation:

After 1 half-life , 500 g of the parent isotope will remain. After 2 half-lives , 250 g of the parent isotope will remain. After 3 half-lives , 125 g of the parent isotope will remain.