1. Half-life

2. Half-life
The time it takes for one half of a sample to undergo radioactive decay
Half-lives vary in length depending on the isotope

5. Half-life Problems
Assuming you have 100% of a sample this is the % left after each half-life.

6. If you have a 200g sample of a radioisotope which has a half-life of 30 years, how much will remain after 150 years?

7. Gold-191 has a half-life of 12. 4 hours
Gold-191 has a half-life of 12.4 hours. What mass of this isotope would remain after hours if you started with a 7.50mg sample of pure 191Au?

8. What is the half-life of an unknown material if 0
What is the half-life of an unknown material if 0.195% remains after 2304 years?

9. If you have a 200g of a radioisotope left after 40years, how much did you start with if the half-life of the isotope is 10 years?

10. If you have a sample of a radioisotope that has a half-life of 15 years, how many years will have passed when 6.25% remains?