Max kept 100 grams of radioactive iodine in a container. He observed the amount of iodine left in the container after regular intervals of time and recorded them in the table shown below:

\begin{tabular}{|c|c|}
\hline Time (days) & Amount of iodine in container (in grams) \\
\hline 0 & 100 \\
\hline 8 & 50 \\
\hline 16 & 25 \\
\hline 24 & 12.5 \\
\hline
\end{tabular}

Based on the observations, which of these is most likely Max's inference?

A. The half-life period of radioactive iodine is 32 days.
B. The half-life period of radioactive iodine is 50 days.
C. After 32 days, the amount of iodine left in the container will be 1.25 grams.
D. After 32 days, the amount of iodine left in the container will be 6.25 grams.



Answer :

Max's observations suggest that the amount of radioactive iodine decreases over time following a predictable pattern. Let's analyze this step by step:

1. Initial Observation:
- At time [tex]\( t = 0 \)[/tex] days, the amount of iodine is 100 grams.

2. After 8 days:
- The amount of iodine in the container is 50 grams. This indicates that the iodine amount reduces to half its initial value in 8 days.

Given this observation, we infer that the half-life period of the radioactive iodine is 8 days.

3. After 16 days:
- We need to calculate the amount of iodine left after 16 days.
- Since the half-life period is 8 days, after one half-life (8 days), the amount is halved to 50 grams.
- After another half-life (another 8 days), the amount will halve again, so after 16 days, the amount of iodine will be:
[tex]\[ \frac{50}{2} = 25 \text{ grams} \][/tex]

4. After 24 days:
- Similarly, after 24 days (which is three half-life periods of 8 days each), the amount of iodine is:
[tex]\[ 100 \times \left( \frac{1}{2} \right)^3 = 100 \times \frac{1}{8} = 25 \text{ grams} \][/tex]

5. After 32 days:
- We need to calculate the amount of iodine left after 32 days, which is four half-life periods.
- The amount of iodine is:
[tex]\[ 100 \times \left( \frac{1}{2} \right)^4 = 100 \times \frac{1}{16} = 6.25 \text{ grams} \][/tex]

Therefore, based on the observations and calculations, the correct inference is:
- After 32 days, the amount of iodine left in the container will be 6.25 grams.

This matches the fourth option in the question. Thus, Max's most likely inference would be:

- After 32 days, the amount of iodine left in the container will be 6.25 grams.