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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=4.5xx10^9xx365xx86400s=1.419xx10^17` s
`lambda=0.693/T = 0.693/(1.429xx10^17)=4.882xx10^(-19) s^(-1)`
Number of `.^238U` atoms in 1g ,
`N="Avogardo.s number"/"Mass number"=(6.023xx10^23)/238=2.530xx10^21`
Number of disintegration per second,
`(dN)/(dt)=lambdaN=4.882xx10^(-18)xx2.530xx10^21`
`=1.235xx10^4 s^(-1)`
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