GLUM
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Hello. The question asks: Another sample of iodine-131 has an activity of 800 Bq.
Calculate how long it will take before its activity decreases to 200 Bq.
I have attached the link to the paper that I got it from as there is also a graph (it's question 2b (ii) ) https://pmt.physicsandmathstutor.com...y%202%20QP.pdf
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Sinnoh
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When the activity has gone down to 200 Bq, that means that two half-lives have passed; the first half-life brings it down from 800 to 400 (to half the original activity), and then the next half-life brings it down from 400 to 200 (half again).
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GLUM
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Hello. I understand that it's 2 half lives but I don't know how many days it takes to decrease to 200 Bq
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