Exam-style question
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How does the shape of a decay graph change as time progresses?.
- A.It becomes steeper over time
- B.It becomes less steep over time
- C.It remains a straight line
- D.It fluctuates randomly
Model answer
What a good answer should say
- It becomes less steep over time
Explanation
Why this works
The evidence shows that as time progresses, the decay graph transitions from a steep slope to a gentler slope, indicating that the rate of decay decreases as fewer radioactive nuclei remain. This implies that the activity diminishes at a slower rate as the substance decays.
Therefore, the conclusion is that the shape of the decay graph reflects the exponential nature of radioactive decay, where the rate of decay is proportional to the remaining quantity.
Common mistake
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