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Assuming the age of the earth to be 10""...

Assuming the age of the earth to be `10""^(10)` yaers, the perccentage of original amount of `U""^(238)` is still in existance on earth is x/10% (nearly)(`T""_(1//2)ofU""^(238)is 4.5xx10""^(9)`years). Then 'x' is

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The correct Answer is:
2
`N/N""_(0)=(e""^(-0.693))""^(t/t""_(1//2)`
`N/N""_(0)=((1)/(2))""^(t/t""_(1//2))=N/N""_(0)=(1/2)""^(2.22)orN=N""_(0)/2""^(n)`
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