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Aradioactive isotope has t(1//2) of 10 d...

Aradioactive isotope has `t_(1//2)` of 10 days. If today 125 g of it is left, what was its weight 40 days earlier ?

A

2g

B

600g

C

1g

D

`1.5g`

Text Solution

Verified by Experts

The correct Answer is:
a
`N=N_(0)((1)/(2))^(n) n=(40)/(10)=4`
`(125)/(1000)=N_(0)((1)/(2))^(4),N_(0)=(125)/(1000)xx2xx2xx2xx2=2g`
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