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The half-life of ""^(238)Ufor alpha - decay is 4.5xx10^(19)years . How many disintegrations per second occur in Ig of ""^(238)U? (Avogadro.s number = 6.023 × 10^(23)" mol"^(-1) ) |
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Answer» Solution :HALF - life `T = 4.5 xx10^(9) xx365xx86400s=1.419xx10^(17)s,` `LAMDA=(0.693)/T = (0.693)/(1.429xx10^(17))=4.882xx10^(-19)s^(-1)`. Number of `""^(238)U` atoms in 1 g , `N = ("Avogardo.s number")/("Mass number") = (6.023 xx10^(23))/(238)= 2.530xx10^(21)` Number of disintegrations PER second, `(dN)/(dt) = lamda N= 4.882 xx10^(-18) XX 2.530 xx10^(21)` `= 1.235 xx10^(4)s^(-1)` . |
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