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The activity of a radioactive substance ...

The activity of a radioactive substance is readuced by 80% in 100 days. Its half life is

A

40 says

B

41 days

C

42 days

D

43.04 days

Text Solution

Verified by Experts

The correct Answer is:
D
`lambda=2.303/t log (N_(0)/N)`
`=2.303/100 log (100/20)`
`=0.01609`
`T=0.693/lambda=0.693/0.01609`
`=43.04` days
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