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A radioactive isotope has half life of 8...

A radioactive isotope has half life of 8 days . If today 125 mg is left over, what was its original weight 32 days earlier?

A

6 g

B

5 g

C

4 g

D

2 g

Text Solution

Verified by Experts

The correct Answer is:
D
`t_(1//2)=8` days
No. of half lives in 32 days,
`n=(32)/(8)=4`
`N_(0)=N. 2^(n)=(125 mg)*2^(4)`
`=125xx16 "mg" =2000` mg
=2 g
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