Respuesta :

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Answer:

After one-half life: 16 mg

After 2-half lives: 8 mg

After 3-half lives: 4 mg

After 4-half lives: 2 mg

After 5-half lives: 1 mg

(5 half-lives) x (8 days/half-life) = 40 days  

or doing it the mathematical way:  Let z be the number of days to be found:

1 mg = 32 mg x (1/2)^(z / 8 days)  

1/32 = (1/2)^(z / 8 days)  

log (1/32) = (z / 8 days) x log (1/2)  

z / 8 days = log (1/32) / log (1/2)

z = 8 days x log (1/32) / log (1/2) = 40 days

Explanation:

Iodine-131 has a half-life of 8 days, then it would it take for the number of unstable nuclei in the sample to be reduced from 1,000 to 125 is 512 days.

How do we calculate total time?

Total time of the reduction of any substance from an initial concentration to a particular concentration will be calculated as:

T = (t)ⁿ, where

n = number of half lives

t = half life time = 8 days

1st half life: 1000 → 500

2nd half life: 500 → 250

3rd half life: 250 → 125

So number of half life times is 3. On putting values we get,

T = (8)³

T = 512 days

Hence total duration of time is 512 days.

To know more about half life time, visit the below link:

https://brainly.com/question/25750315