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7/8th of the active nuclei present in a ...

`7/8th` of the active nuclei present in a radioactive sample has decayed in 8 s. The half-life of the sample is

A

(a) 2s

B

(b) 1s

C

(c) 7s

D

(d) 8/3 s

Text Solution

Verified by Experts

The correct Answer is:
D
Number of nuclei left `=1/8th`
Now, `1/8=(1/2)^n`
`:. N`= number of half-lives
`=3`
`3`half-lives=`8s`
`:.` 1half-life`=8/3s`
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