A bone fragment was found from an elk which had died 90 years before. What percent of Pb-210 remains? The half-life if Pb-210 is 22 years.

Question

A bone fragment was found from an elk which had died 90 years before. What percent of Pb-210 remains? The half-life if Pb-210 is 22 years.

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Reagan 4 weeks 2021-09-19T07:53:17+00:00 1 Answer 0

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    2021-09-19T07:54:54+00:00

    Answer:

      about 5.9%

    Step-by-step explanation:

    We assume that the original amount of Pb-210 present at death decays at the given rate. The fraction (f) remaining is multiplied by 1/2 every 22 years, so can be modeled by …

      f = (1/2)^(t/22) . . . . . where t is in years after death

    Then, for t=90, the remaining fraction is …

      f = (1/2)^(90/22) ≈ 0.05868 ≈ 5.9%

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