P4: Atoms & Nuclear Radiation Physics GCSE

• What is radioactive decay?

  The process of unstable nuclei emitting radiation
• Why are some atomic nuclei unstable?

  Due to an imbalance in forces within the nucleus
• How does Carbon-14 differ from Carbon-12?

  Carbon-14 has two extra neutrons
• What happens when unstable nuclei emit radiation?

  They become more stable
• What is the term for the process of emitting radiation?

  Radioactive decay
• Is radioactive decay a predictable process?

  No, it is a random process
• What is the definition of activity in terms of radiation?

  The rate at which unstable nuclei decay
• How is activity measured?

  In Becquerels (Bq)
• What does 1 Becquerel represent?

  1 nucleus decaying in 1 second
• How can radiation be detected?

  By using photographic film or Geiger counters
• What is the difference between activity and count rate?

  Activity is decay rate; count rate is detection rate
• What type of radiation is emitted from unstable nuclei?

  Nuclear radiation
• What are the four types of radiation emitted?

  Alpha, beta, gamma, and neutrons
• What is the symbol for alpha particles?

  α
• What is an alpha particle equivalent to?

  A helium nucleus
• What charge do alpha particles have?

  +2
• What is the symbol for beta particles?

  β
• What are beta particles?

  Fast-moving electrons emitted from nuclei
• What charge do beta particles have?

  -1
• What is the symbol for gamma rays?

  γ
• What are gamma rays?

  Electromagnetic waves with high energy
• What is the charge of gamma rays?

  They have no charge
• What is the symbol for neutrons?


  n
• What is the charge of neutrons?

  They have no charge
• How do alpha, beta, and gamma radiation differ in penetrating power?

  Alpha is least; gamma is most penetrating
• What material stops alpha radiation?

  Paper
• What material stops beta radiation?

  A few millimeters of aluminium
• What material can gamma rays partially pass through?

  Thick lead
• What is ionising power?

  The ability to change the charge of atoms
• Which type of radiation is the most ionising?

  Alpha radiation
• Which type of radiation is the least ionising?

  Gamma radiation
• How does the range of alpha radiation in air compare to gamma radiation?

  Alpha travels a few centimeters; gamma has infinite range
• Why is alpha radiation used in smoke detectors?

  It is the most ionising and weakly penetrating
• What happens when smoke enters a smoke detector?

  It blocks alpha particles, triggering the alarm
• What are the uses of radiation?

  • Producing electricity through nuclear fission
  • Medical procedures (diagnosis and treatment)
  • Testing materials
  • Determining the age of ancient artifacts
  • Checking the thickness of materials
  • Smoke detectors
• What are the properties of alpha, beta, and gamma radiation?

  • Alpha: least penetrating, most ionising
  • Beta: moderate penetrating, moderate ionising
  • Gamma: most penetrating, least ionising
• Why is it important to understand the properties of different types of radiation?

  • To determine suitable applications
  • To assess safety and health risks
  • To understand detection methods
• What should students remember about the terms unstable, random, and decay?

  • They have specific meanings in this topic
  • Use them correctly in answers
• Why is it important to distinguish between activity and count rate?

  • Activity refers to decay rate
  • Count rate refers to detection rate
• What is the significance of ionising capability in radiation?

  • Determines harmful effects on living tissue
  • Influences safety measures and regulations