The isotope 238 U decays to 206Pb with a half-life of 4.47 x 10° y. (Although the decay occurs in many individual steps, the first step hasby far the longest half-life, so the decay can be considered to go straight to lead.) A rock recovered far underground is found to contain0.76 mg of 238U, 0.17 mg of 206pb, and 1.4 mg of 40 Ar. Assume that 40K decays to only 40 Ar with a half-life of 1.25 x 10 y. How much40K will it likely contain?mg

Given:For U to Pb decay half time is TPb = 4.47×109 yearsinital U mass, Mi = 0.76 + 0.17 mg =…

Answered: The isotope 238 U decays to 206Pb with…

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