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A sample of radioactive element has a ma...

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

A

`1.35 g`

B

`2.50 g`

C

`3.70 g`

D

`6.30 g`

Text Solution

Verified by Experts

The correct Answer is:
a
Let `t=0, M_(0) =10g`
`t=2 tau 2((1)/(lambda))`
Then,
`M=M_(0) e^(- lambdat) =10e^(-lambda)((2)/(lambda)) =10((1)/(e))^(2)1.35g `.
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