IGCSE · 5 · multiple choice
Nuclear physics · Question 3
Nuclear physics · Original GioPhysics question with a detailed, mark-by-mark answer guide.
- Demand
- routine
- Marks
- 1
- Topics
- 1
- Answer
- Complete
multiple choice1 mark
A sample of a radioactive isotope has an activity of 800 Bq. The half-life of the isotope is 6.0 hours. What is the activity after 24 hours?
- A
0 Bq
- B
50 Bq
- C
200 Bq
- D
400 Bq
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Answer overviewCorrect answer: B — 50 Bq
01
1 markAnswer and reasoning
How to approach it
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
The correct choice is B: 50 Bq
- 2
24 hours is four half-lives, so the activity is halved four times: 800 → 400 → 200 → 100 → 50. C and D are the answers of candidates who stop after one or two halvings.
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