Answer:
As-81 undergoes radioactive decay with a half-life of 33 seconds. This means that after 33 seconds, half of the original sample would have decayed, and after another 33 seconds, half of the remaining sample would have decayed, and so on.
To find the percent of the sample that remains un-decayed after 43.2 seconds, we can use the following formula:
percent remaining = (1/2)^(t/h) x 100%
where t is the time elapsed and h is the half-life.
Substituting the given values, we get:
percent remaining = (1/2)^(43.2/33) x 100%
percent remaining ≈ 23.2%
Therefore, about 23.2% of the As-81 sample remains un-decayed after 43.2 seconds.
Step-by-step explanation: