Half-life Quiz
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5 questions, one answer each
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1. An isotope has a half-life of 4 days. What fraction of the sample is left after 12 days?
- A. 1/4
- B. 1/6
- C. 1/8
- D. 1/12
2. A sample has an activity of 200 Bq. After 2 hours its activity is 50 Bq. What is its half-life?
- A. 1 hour
- B. 2 hours
- C. 4 hours
- D. 0.5 hours
3. Which is the best choice for a medical tracer?
- A. An alpha emitter with a half-life of 500 years
- B. A beta emitter with a half-life of 30 years
- C. An alpha emitter with a half-life of 6 hours
- D. A gamma emitter with a half-life of 6 hours
4. What does a decay curve show?
- A. How the mass of a sample changes
- B. How activity falls with time
- C. How radiation travels through air
- D. How count rate depends on distance
5. A wooden bowl contains one eighth of the carbon-14 of a living tree. The half-life of carbon-14 is 5730 years. How old is the bowl?
- A. 11 460 years
- B. 5730 years
- C. 17 190 years
- D. 22 920 years