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InterviewSolution
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If `20 gm` of a radioactive substance due to radioactive decay reduces to `10 gm` in `4` minutes, then in what time `80 gm` of the same substance will reduce to `10 gm` ?A. 8 minutesB. 12 minutesC. 16 minutesD. 20 minutes |
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Answer» Correct Answer - B (b) `20 gm` substance reduces to `10 gm` (i.e., becomes half in `4 min`. So `T_(1//2) = 4 min`. Again `M = M_0 ((1)/(2))^(t//T_1//2)` `rArr 10 = 80((1)/(2))^(t//4) rArr (1)/(8) = ((1)/(2))^3 = ((1)/(2))^(t//4)` `rArr t = 12 min`. |
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