Half-Life Worksheet

1) Fluorine-21 has a half life of approximately 5 seconds. What fraction of the original nuclei would remain after 1 minute?


2) Iodine-131 has a half life of 8 days. What fraction of the original sample would remain at the end of 32 days?



3) The half-life of chromium-51 is 28 days. If the sample contained 510 grams, how much chromium would

remain after 56 days?


4) How much would remain after 1 year? (refer to question #3)


5) The half life of Uranium-238 is 4.5 billion years and the age of earth is 4.5 X 10^9 years. What fraction of Uranium-238 that was present when Earth was formed still remains?


6) Chromium-48 decays. After 6 half-lives, what fraction of the original nuclei would remain?


7) The half life of iodine-125 is 60 days. What fraction of iodine-125 nuclides would be left after 360 days?


8) Titanium-51 decays with a half life of 6 minutes. What fraction of titanium would remain after one hour?


9) A medical institution requests 1 g of bismuth-214, which has a half life of 20 min. How many grams of bismuth-214 must be prepared if the shipping time is 2 h?
 
10) The half life of radium 226 is 1602 years. What fraction of a sample radium-226 would remain after 9612 years?
 
Answers: (coming soon)