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Radioactive Half-Life quiz

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  • What is the definition of radioactive half-life?
    Radioactive half-life is the amount of time required for half of a radioisotope to decay.
  • What is a radioisotope or nuclide?
    A radioisotope or nuclide is an isotope with an unstable nucleus that emits radiation as it decays.
  • Name two types of radioactive decay mentioned in the lesson.
    Two types of radioactive decay mentioned are alpha decay and beta decay.
  • What is the formula for calculating radioactive half-life?
    The formula is t₁/₂ = ln(2)/k, where k is the decay constant.
  • What is the approximate value of ln(2) used in the half-life equation?
    The approximate value of ln(2) is 0.693.
  • What does the decay constant (k) represent in the half-life equation?
    The decay constant (k) represents the probability per unit time that a nucleus will decay.
  • Is the half-life of a radioisotope dependent on its initial concentration?
    No, the half-life is not dependent on the initial concentration of the substance.
  • If a sample starts with 100% of a radioisotope, what percentage remains after one half-life?
    After one half-life, 50% of the original radioisotope remains.
  • How does the percentage of a radioisotope change after two half-lives?
    After two half-lives, 25% of the original radioisotope remains.
  • What does a plot of half-life versus time look like for a radioisotope?
    The plot is a flat, straight line, indicating that half-life remains constant over time.
  • If a radioisotope has a half-life of 3 days, how much of the original sample remains after 6 days?
    After 6 days (two half-lives), 25% of the original sample remains.
  • What is the relationship between half-life and the decay constant?
    Half-life is inversely proportional to the decay constant.
  • Why is understanding half-life important in nuclear medicine?
    Understanding half-life is important in nuclear medicine for determining how long a radioisotope will remain active in the body.
  • What order of reaction does radioactive decay follow according to the lesson?
    Radioactive decay follows first order rate law rules.
  • What happens to the half-life if the decay constant increases?
    If the decay constant increases, the half-life decreases.