Lecture 14 Homework Problems
Radioactive Decay

1. Table 20.1 of the text gives a list of radioactive parent isotopes and the stable daughter products, showing different half-lives. (a) What percentage of each radioactive parent isotope would still remain in a rock that is 4.5 billion years old (i.e. was formed at the beginning of the solar system)? (b) What ratio of daughter to parent isotopes would you measure in each case? If your measurement is only good to 10% (a 10:1 ratio), which isotope pairs (parent-daughter pairs) would be useful in measuring the date of your rock?