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Reading Decay Counts Over Different Intervals 4 questions
Reading Decay Counts Over Different Intervals
Base your answers on the information provided and your knowledge of chemistry. Use the 2025 Chemistry Reference Tables as needed.
A simulation predicts detector counts for a sample with a constant half-life. Each row gives the expected count from the sample alone over a short recording. For this model, treat the rate as constant during each recording and proportional to the parent nuclei remaining.
| Elapsed time (h) | Counting interval (min) | Emissions counted |
|---|---|---|
| 0 | 2.0 | 80 |
| 4 | 4.0 | 80 |
Question 1
Calculate the count rate in emissions per minute at each elapsed time.
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Question 2
Which half-life best fits the change in the model’s count rate?
- 2 h
- 4 h
- 6 h
- 8 h
The class wants to predict the expected count for a new three-minute recording eight hours after the start. Continue using the same model.
Question 3
Predict the expected count in that recording. Show how the elapsed time and the recording duration are used.
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Question 4
A student says the first two rows prove no decay occurred because both show 80 emissions. Explain why the recording intervals matter.
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