half lifes

Cards (23)

  • What are the two terms discussed in the video?
    Activity and half-life
  • What happens to unstable isotopes to become more stable?
    They decay by emitting radiation
  • What do we call materials that contain unstable isotopes?
    Radioactive materials
  • Why can't we predict when a single radioactive isotope will decay?
    Because the decay process is random
  • What can we determine from a large sample of radioactive isotopes?
    Activity and half-life of the sample
  • How is activity measured?
    In becquerels
  • What does one becquerel represent?
    One decay per second
  • If a sample has an activity of 600 becquerels, how many isotopes decay each second?
    600 isotopes decay each second
  • What is half-life defined as?
    The time for radioactive nuclei to halve
  • How can half-life be defined in terms of activity?
    As the time taken for activity to halve
  • If a sample starts with 1 million unstable nuclei, how many will remain after one half-life?
    500,000 unstable nuclei
  • How does the decay process affect the overall rate of decay?
    It decreases as fewer particles remain
  • What does a graph of activity against time show?
    Decline in particles and activity over time
  • How do you calculate half-life from a graph?
    Find time for activity to halve
  • What is the half-life of the sample in the example given?
    Two hours
  • What device is used to find the activity of a radioactive sample?
    Geiger-Muller tube
  • What does a Geiger-Muller tube record?
    Decays that reach it each second
  • What is the count rate used for?
    To estimate the activity of a sample
  • If the half-life of a radioactive source is 40 hours, how many half-lives are in 5 days?
    Three half-lives
  • How many radioactive nuclei remain after three half-lives from 3 million?
    375,000 radioactive nuclei
  • What are the key concepts of radioactive decay discussed in the video?
    • Activity: overall rate of decay
    • Half-life: time for nuclei or activity to halve
    • Random decay process
    • Decrease in activity over time
  • How do the concepts of activity and half-life relate to each other?
    • Fewer radioactive nuclei lead to lower activity
    • Both concepts are correlated
    • Activity decreases as half-life progresses
  • How do you determine the remaining radioactive nuclei after multiple half-lives?
    1. Calculate total time in hours
    2. Divide by half-life to find half-lives
    3. Halve the initial amount for each half-life