Question

What percentage of a radioactive species would be found as daughter material after five half-lives?
A.
50%
B.
25%
C.
15%
D.
12.5%
E.
3.125%

Answer 1

To determine the percentage of a radioactive species that would be found as daughter material after five half-lives, we need to understand how the process works.

During each half-life, half of the remaining parent radioactive species decays into the daughter material.

After:
1. **1st half-life**: 50% parent remaining, 50% daughter
2. **2nd half-life**: 25% parent remaining, 75% daughter
3. **3rd half-life**: 12.5% parent remaining, 87.5% daughter
4. **4th half-life**: 6.25% parent remaining, 93.75% daughter
5. **5th half-life**: 3.125% parent remaining, 96.875% daughter

Therefore, after five half-lives, the percentage of the radioactive species found as daughter material would be approximately 96.875%. The question asks for the percentage of the remaining parent material.

To summarize:
- The percentage of daughter material after five half-lives is approximately **96.875%**.
- The percentage of parent material remaining is **3.125%**.

So if you are looking for how much of the parent material remains (which seems to be implied based on options), the answer among the choices given is:

**E. 3.125%**.