Radioactive Decay and Half-Life: Quiz
Seven questions on nuclear equations, types of radiation, penetrating power and half-life calculations, with explanations.
Radioactive Decay and Half-Life: Quiz
7 questions
Neutrons = mass number − atomic number = 14 − 6 = 8.
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Answer: 8
Neutrons = mass number − atomic number = 14 − 6 = 8.
Alpha decay removes 4 from A and 2 from Z: 226 − 4 = 222 and 88 − 2 = 86, which is radon.
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Answer: radon-222 (Z = 86)
Alpha decay removes 4 from A and 2 from Z: 226 − 4 = 222 and 88 − 2 = 86, which is radon.
A stays 234 and Z rises by 1, so X has A = 0 and Z = −1: an electron, ⁰₋₁e.
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Answer: a beta particle (electron)
A stays 234 and Z rises by 1, so X has A = 0 and Z = −1: an electron, ⁰₋₁e.
Alpha particles are heavy and doubly charged, so they lose their energy quickly. Beta needs aluminium; gamma is only reduced by thick lead.
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Answer: alpha
Alpha particles are heavy and doubly charged, so they lose their energy quickly. Beta needs aluminium; gamma is only reduced by thick lead.
n = 6.0 h ÷ 2.0 h = 3.0 half-lives, so 160 mg × (½)³ = 20 mg.
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Answer: 20 mg
n = 6.0 h ÷ 2.0 h = 3.0 half-lives, so 160 mg × (½)³ = 20 mg.
1200 Bq → 600 Bq → 300 Bq is 2 half-lives, so t½ = 16 days ÷ 2 = 8 days.
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Answer: 8 days
1200 Bq → 600 Bq → 300 Bq is 2 half-lives, so t½ = 16 days ÷ 2 = 8 days.
Positron emission keeps A the same and lowers Z by 1: Z = 8 is oxygen, so ¹⁸₉F → ¹⁸₈O + ⁰₊₁e.
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Answer: oxygen-18 (Z = 8)
Positron emission keeps A the same and lowers Z by 1: Z = 8 is oxygen, so ¹⁸₉F → ¹⁸₈O + ⁰₊₁e.