A radioactive isotope has a half-life of 8 days. A hospital in Barbados receives a sample with an initial activity of 800 Bq. What will be the activity of the sample after 24 days?

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Question

A radioactive isotope has a half-life of 8 days. A hospital in Barbados receives a sample with an initial activity of 800 Bq. What will be the activity of the sample after 24 days?

Accepted Answer

100 Bq — Award 1 mark for correct calculation. After 24 days, 3 half-lives have elapsed (24 ÷ 8 = 3). Activity = 800 → 400 → 200 → 100 Bq. B is incorrect — this represents only 2 half-lives. C is incorrect — this represents only 1 half-life. D is incorrect — this would require 4 half-lives (32 days).

Answer

400 Bq

Answer

100 Bq

Answer

200 Bq

Answer

50 Bq

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