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The half-life of ^238U92 against alpha d...

The half-life of `_^238U_92` against alpha decay is `4.5xx10^9` year. How much disintegration per second occurs in 1 g of `_^238U_92` ?

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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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