Exam-style question
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What does a decay graph typically show about the activity of a radioactive substance over time?.
- A.Activity decreases exponentially over time
- B.Activity remains constant over time
- C.Activity increases exponentially over time
- D.Activity decreases linearly over time
Model answer
What a good answer should say
- Activity decreases exponentially over time
Explanation
Why this works
The evidence from decay graphs shows that the activity of a radioactive substance decreases in an exponential manner as time progresses. This indicates that the rate of decay is proportional to the amount of substance remaining.
The implication is that as the substance decays, fewer radioactive nuclei are available to decay, leading to a decrease in activity. Thus, the conclusion is that radioactive decay is a random process that follows an exponential decay pattern.
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