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how much of a radioactive kind of bismuth will be left after 40 min if the half life is 20 min and you start with 960 grams?

1 Answer

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If the half life is 20 minutes, then in 40 minutes there is 2 half lives. At the end of Each half life, you will have 1/2 of the sample remaining. So...

After 20 min you have

960/2 = 480

After 40 minutes you will have

480/2 = 240 grams
User Maryam Homayouni
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