Radioactivity and Half Life

• What is the unit of activity in radioactivity?

  Becquerels (Bq)
• What does count rate measure in radioactivity?

  Number of radiation counts per second
• What is radioactive contamination?

  Unwanted radioactive atoms on an object
• What is irradiation?

  Exposure of an object to nuclear radiation
• What precautions should be taken against irradiation?

  • Keep sources in lead-lined boxes
  • Stand behind barriers or in a different room
  • Handle sources with remote-controlled arms
• What device measures radiation counts?

  Geiger-Müller tube and counter
• What is half-life in radioactivity?

  Time for the number of nuclei to halve
• What happens to activity during one half-life?

  Activity or count-rate halves
• Which type of radiation is most dangerous inside the body?

  Gamma (γ) radiation
• Which type of radiation is least dangerous outside the body?

  Alpha (α) radiation
• What are the potential risks of radiation exposure?

  • Damaged cells can multiply and become cancerous
  • Cells can be damaged
  • Cells can be killed
• What type of radiation is gamma (γ)?

  Electromagnetic radiation
• What can gamma radiation penetrate?

  Thick sheets of lead
• What is a beta particle?

  A neutron converted into a proton
• How does radiation affect living cells?

  It can ionize atoms within them