A radioactive isotope has a half-life of 20 days. If 100 g of the substance is taken, the weight of the isotope remaining after 40 days isA. 25 gB. 2.5 gC. 60 gD. 40 g

A radioactive isotope has a half-life of 20 days. If 100 g of the subs

1.	A radioactive isotope has a half-life of 20 days. If 100 g of the substance is taken, the weight of the isotope remaining after 40 days isA. 25 gB. 2.5 gC. 60 gD. 40 g
Answer» Correct Answer - A `n = (40)/(20) = 2` `:.` Amount left `(N_(0))/(2^(n)) = (100)/(2^(2)) = 25g`

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A radioactive isotope has a half-life of 20 days. If 100 g of the substance is taken, the weight of the isotope remaining after 40 days isA. 25 gB. 2.5 gC. 60 gD. 40 g

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