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Quiz Chapter 8: Radioactivity

10 questions · Form 3 Science Bab 8: Radioactivity

10 questions · plays in fullscreen

Full Question List & Answer Key

Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.

1. Which radiation particle has the HIGHEST ionising power?

  1. Gamma ray
  2. Beta particle
  3. Alpha particle
  4. X-ray
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Answer: C

Alpha particles have the highest ionising power due to their relatively large mass and double positive charge (+2).

2. What unit is used to measure the biological dosage effect of background ionising radiation on human tissue?

  1. Joule (J)
  2. Sievert (Sv)
  3. Watt (W)
  4. Becquerel (Bq)
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Answer: B

The Sievert (Sv), or microSievert ($\μSv$), measures equivalent biological radiation dose absorbed by human bodies.

3. What safety tool should be used when handling unsealed radioactive laboratory sources to avoid direct contact?

  1. Rubber gloves only
  2. Robotic arms or long forceps/tongs
  3. Bare hands washed with soap
  4. Plastic tweezers
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Answer: B

Long tongs, forceps, or robotic arms maintain safe distance, reducing radiation exposure intensity according to the inverse-square law.

4. Which source contributes to NATURAL background radiation in our environment?

  1. Nuclear weapons testing fallout
  2. Diagnostic medical X-ray scans
  3. Radon gas from surrounding rocks and soil
  4. Radioactive waste from nuclear power plants
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Answer: C

Radon gas emitted naturally from soil and rocks containing uranium is a major natural source of background radiation.

5. Which radioisotope is injected into liquid pipelines to detect underground leaks?

  1. Sodium-24
  2. Cobalt-60
  3. Carbon-14
  4. Iodine-131
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Answer: A

Sodium-24 is a short-lived radioisotope added to liquids; detectors trace leak locations where radiation accumulates outside pipes.

6. Why are radioactive substances safely stored inside thick lead containers?

  1. Lead neutralizes nuclear decay permanently.
  2. Lead absorbs penetrating ionising radiation like gamma rays.
  3. Lead increases the half-life of radioactive materials.
  4. Lead prevents chemical reactions with surrounding air.
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Answer: B

Lead has a high density and high atomic number, making it highly effective at absorbing alpha, beta, and penetrating gamma rays.

7. Which type of radioactive ray has the HIGHEST penetrating power and requires thick lead or concrete to stop it?

  1. Alpha particle
  2. Beta particle
  3. Gamma ray
  4. Cosmic ray
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Answer: C

Gamma rays are high-energy electromagnetic waves with no mass or charge, giving them extremely high penetrating power.

8. Which radioactive isotope is commonly used in medicine for cancer radiotherapy treatment?

  1. Carbon-14
  2. Cobalt-60
  3. Sodium-24
  4. Phosphorus-32
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Answer: B

Cobalt-60 emits high-energy gamma rays used in radiotherapy to destroy cancerous tumor cells.

9. What is the S.I. unit for measuring radioactivity decay rate?

  1. Sievert (Sv)
  2. Curie (Ci)
  3. Becquerel (Bq)
  4. Gray (Gy)
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Answer: C

The S.I. unit of radioactivity is the Becquerel (Bq), defined as one decay per second.

10. Who among the following scientists discovered radioactivity in 1896 using uranium compounds?

  1. Marie Curie
  2. Henri Becquerel
  3. Wilhelm Röntgen
  4. Ernest Rutherford
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Answer: B

Henri Becquerel discovered radioactivity in 1896 when uranium compounds spontaneously emitted rays that blackened photographic plates.

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