A radioisotope has half life of 10 years...

A radioisotope has half life of 10 years. What percentage of the original amount of it would you expect to remain after 20 years? a)0 b)12.5 c)25 d)8

A

0

B

12.5

C

8

D

25

Verified by Experts

The correct Answer is:

D

`t_(1//2)` = 10 yrs , t = 20 yrs
`therefore n = t/(t_(1//2)) = 20/10 = 2 `
`N = (N_0)/(2^2) = 1/4 N_0 = 1/4 xx 100% ` of ` N_0 = 25`

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