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A sample of a radioactive element has a ...

A sample of a radioactive element has a mass of `10 g` at an instant `t=0`. The approxiamte mass of this element in the sample after two mean lives is .

A

`1.35g`

B

`2.50g`

C

`3.70g`

D

`6.30g`

Text Solution

Verified by Experts

The correct Answer is:
A
`t=2tau=2xx1.44T=2.88T`
As `N/(N_(0))=m/(m_(0)) =(1/2)^(t//T)=(1/2)^(2.38)`
`:. m=m_(0)(1/2)^(2.88)=10(1/2)^(2.88)g`
`=10xx0.135g=1.35g`
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