Step 1: Determine the fraction of the original atoms remaining.
The problem states that the radioactive element decayed to 81 of its original atoms. This means the fraction remaining (N/N0) is 81.
Step 2: Calculate the number of half-lives (n).
The formula for radioactive decay is:
N0N=(21)n
Substitute the given fraction:
81=(21)n
Since 23=8, we can write 81 as (21)3.
(21)3=(21)n
Therefore, the number of half-lives (n) is 3.
Step 3: Calculate the half-life (T1/2).
The total time elapsed (t) is given as 6 minutes. The relationship between total time, number of half-lives, and half-life period is:
t=n×T1/2
Substitute the known values:
6minutes=3×T1/2
Now, solve for T1/2:
T1/2=36minutes
T1/2=2minutes
The final answer is 2minutes.
3 done, 2 left today. You're making progress.