Sub-topic 1
2024 · National Preliminary
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Fossil dating and the geological time scale: true/false
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Sub-topic 2
2026 · National Preliminary
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Fossil dating and the geological time scale: true/false
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Sub-topic 3
2023 · National Preliminary
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Finding half-life from initial and final mass of a decaying radioisotope
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Sub-topic 4
2025 · National Preliminary
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Finding half-life from initial and final mass of a decaying radioisotope
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Sub-topic 5
2026 · National Preliminary
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Finding half-life from initial and final mass of a decaying radioisotope
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Sub-topic 6
2026 · National Preliminary
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Activity of a radioactive sample from decay constant and number of nuclei
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Sub-topic 7
2023 · National Preliminary
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Mass remaining after a given number of half-lives
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Sub-topic 8
2023 · National Preliminary
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Mass remaining after a given number of half-lives
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Sub-topic 9
2026 · National Preliminary
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Mass remaining after a given number of half-lives
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Sub-topic 10
2026 · National Semifinal
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Mass remaining after a given number of half-lives
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Sub-topic 11
2026 · National One-Eighth
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Radioactive decay: activity after a whole number of half-lives
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Sub-topic 12
2026 · National One-Eighth
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Activity of a radionuclide from the decay constant
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Sub-topic 13
2026 · National One-Eighth
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Decay constant from half-life
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Sub-topic 14
2025 · National Quarterfinal
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Identifying the final nuclide of a decay chain
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Sub-topic 15
2023 · National One-Eighth
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Half-life from a ratio of activities
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Sub-topic 16
2026 · National Preliminary
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Suitability and limitations of carbon-14 dating (true/false)
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Sub-topic 17
2026 · National Preliminary
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Time elapsed for a radionuclide sample to decay to a given mass, from its half-life
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Sub-topic 18
2013 · National Preliminary
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Definition of the half-life of a radioactive substance
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Sub-topic 19
2013 · National Preliminary
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Decay constant from half-life
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Sub-topic 20
2013 · National Preliminary
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Radioactive decay rate is proportional to, not equal to, the number of particles present (true/false)
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Sub-topic 21
2016 · National One-Eighth
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Half-life of a radioactive substance from its decay constant
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Sub-topic 22
2016 · National One-Eighth
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Percentage of initial activity remaining after several half-lives
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Sub-topic 23
2017 · National Quarterfinal
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Types of radioactive decay: beta, alpha and gamma, and their nuclear changes
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Sub-topic 24
2021 · National Semifinal
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Activity of a radionuclide after elapsed time, via the exponential decay law
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Sub-topic 25
2023 · National Preliminary
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Number of half-lives for a 192g sample to decay to 0.375g
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Sub-topic 26
2023 · National Preliminary
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Half-life from decay of 56.0mg to 1.75mg in 12 hours
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Sub-topic 27
2023 · National Quarterfinal
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Decay time from initial and final mass given a half-life, 2.3min half-life
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Sub-topic 28
2023 · National Quarterfinal
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Half-life from a specimen's activity decreasing 64x in a given time
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