1. If 90% of a sample has decayed, what fraction of the sample remains? 2. If the fraction of a sample that has decayed is 0.4, what percentage of the sample remains? 3. The nucleus of plutonium-239 undergoes radioactive decay with a half-life of 24,400 years. In a sample containing 239Pu, What percentage of 239Pu isotopes remain after exactly 4 half-lives? 4. The half-life of carbon-14 is 5730 yr. What fraction of the original carbon-14 in a sample has decayed after 4,297.5 years? 5. Fluorine-18, a radioactive isotope used in nuclear medicine has a half-life of 1.8 h. How long will it take for 87.5% of the 18F nuclei in a sample to decay? 6. The nucleus of plutonium-239 undergoes radioactive decay with a half-life of 24,400 years. In a sample containing 239Pu, After how many years will 25% of the original 239Pu nuclei remain?
1. If 90% of a sample has decayed, what fraction of the sample remains?
2. If the fraction of a sample that has decayed is 0.4, what percentage of the sample remains?
3. The nucleus of plutonium-239 undergoes radioactive decay with a half-life of 24,400 years. In a sample containing 239Pu, What percentage of 239Pu isotopes remain after exactly 4 half-lives?
4. The half-life of carbon-14 is 5730 yr. What fraction of the original carbon-14 in a sample has decayed after 4,297.5 years?
5. Fluorine-18, a radioactive isotope used in nuclear medicine has a half-life of 1.8 h. How long will it take for 87.5% of the 18F nuclei in a sample to decay?
6. The nucleus of plutonium-239 undergoes radioactive decay with a half-life of 24,400 years. In a sample containing 239Pu, After how many years will 25% of the original 239Pu nuclei remain?
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