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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

2.50 g

B

3.70 g

C

6.30 g

D

1.35 g

Text Solution

Verified by Experts

The correct Answer is:
D
`M = M_(0) e^(-lambda t)`. Since `t = (2)/(lambda)`, we get
`rArr M = 10 xx e^(-lambda xx (2)/(lambda)) = 10 e^(-2) = 1.35` gram.
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