Radioactivity, Uses & Dangers Quiz
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5 questions, one answer each
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1. What is the unit of radioactive activity?
- A. Volt
- B. Becquerel
- C. Newton
- D. Ohm
2. Why does the activity of a radioactive sample decrease over time?
- A. Because the nuclei get heavier
- B. Because there are fewer undecayed nuclei left to decay
- C. Because the sample cools down
- D. Because gravity weakens the radiation
3. A patient accidentally swallows a radioactive tracer. Is this contamination or irradiation?
- A. Irradiation, because radiation from outside the body reaches the patient
- B. Contamination, because the radioactive material is now inside the patient's body
- C. Neither, since tracers are not radioactive
- D. Both equally, with no meaningful difference
4. A radioactive isotope has an initial activity of 640 Bq and a half-life of 5 minutes. What is its activity after 20 minutes?
- A. 160 Bq
- B. 40 Bq
- C. 80 Bq
- D. 320 Bq
5. Why is beta radiation, rather than alpha or gamma, typically used in a paper-thickness gauge?
- A. Beta is completely absorbed by any thickness of paper, so no beta ever gets through
- B. Beta has a penetrating range where small changes in paper thickness cause a measurable change in the amount transmitted
- C. Alpha and gamma cannot be detected by any instrument
- D. Beta radiation is not ionising, so it is safer to use