Radioactive decay & Half-life

• Can you tell when an individual nucleus will decay

  No the process is random
• What is the activity of a radioactive sample

  Overall rate of decay of all the radioactive isotopes in a sample
• Units for activity

  Becquerels (Bq)
• Half-life

  1.Time taken for the activity to halve

  2.Time taken for the number of radioactive nuclei in a sample to halve
• How do you find the half life from an activity-time graph

  Time it takes for activity to fall by half
• What device is used to record radioactive decays

  Geiger-Muller tube and counter
• Count rate

  Number of decays measured each second by a Geiger-Muller tube