MYP Physics · 17 · multiple choice
Random nuclei, predictable samples
Atomic and nuclear physics · Original GioPhysics question with a detailed, mark-by-mark answer guide.
- Demand
- recall
- Marks
- 3
- Topics
- 1
- Answer
- Complete
Which statement about radioactive decay is correct?
- A
The exact decay time of each nucleus can be predicted
- B
Heating a sample makes every nucleus decay immediately
- C
Individual decays are random, but a large sample has a predictable statistical pattern
- D
A detector records every decay with no background counts
- a
Select and explain Select the correct statement and explain what ‘random’ means in this context.
3 marks
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a
Select and explain Select the correct statement and explain what ‘random’ means in this context.
Predict from the governing principle before looking for a matching option. Then reject alternatives by checking direction, units, limiting behaviour or the physical meaning of each statement.
- 1
Selects option C: individual nuclear decays are random, while a large sample follows a predictable statistical pattern.
- 2
Explains that the time at which one particular unstable nucleus decays cannot be predicted.
- 3
Explains that probabilities allow the behaviour of many nuclei, such as half-life, to be predicted.
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