## Half-Life Questions

## 1. What is a becquerel?

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## 2. What is the half-life of a radioactive isotope?

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## 3. Another substance has a half-life of 3 hours.

What fraction of the atoms will have decayed after 6 hours?

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## 4. A radioactive substance activity falls from 8,000 counts per minute to 500 counts per minute in 20 hours. What is the half-life of the substance?

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## 5. After the 3rd half-life, how much of the sample is left?

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## 6. After the second half-life, how much of the sample is left?

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## 7. What does the beta particle have a charge of?

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## 8. If Carbon-14 has a half-life of 5,730 years, how old is a fossil if it has undergone 4 half-lives?.

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## 9. If Carbon-12 has a half-life of 5,730 years, how old is a fossil if it has undergone 7half-lives?

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## 10. An isotope has a half-life of 6 hours, what percentage of the isotope will be left after 24 hours?

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