RADIOACTIVITY EXERCISE SHEET

1.    You start out with 10,000 atoms of an unstable, radioactive isotope.

        After 1 half life, how many parent atoms are there?

        How many daughter atoms are there?

        After 2 half lives, how many parent and how many daughter atoms are there?

2.    You find that the ratio of parent: daughter atoms is 500:500.

        a.    How many half lives have passed?

        b.     If the ratio is 1250:8750 how many half lives have passed?

        If the length of a half life is 5700 years, how old are the samples in a and b. above?