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InterviewSolution
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The half-life of a radioactive isotope `X` is `20` years. It decays to another element `Y` which is stable. The two elements `X` and `Y` were found to be in the ratio of `1 : 7` in a sample of a given rock. The age of the rock was estimated to be.A. 40 yearsB. 60 yearsC. 80 yearsD. 100 years |
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Answer» Correct Answer - B Half-life of `X rArr T_(X)=20` years `underset(1)overset("Active")X underset(" ")to underset(7)overset("Stable")Y` `(N)/(N_(0))=(1)/(1+7)=(1)/(8)=(1)/(2^(n))=(1)/(2^(3))` `n=3=(t)/(T)=(t)/(20)` `t=60` years. |
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