Hazards&Uses of Radioactive Emissions& Background Radiation

• What is background radiation?


  It is the radiation that exists around us all the time.
• Why is it important to remember that radiation is a natural phenomenon?


  Because radioactive elements have always existed on Earth and in outer space.
• How has human activity affected background radiation levels?


  Human activity has added to the amount of radiation that humans are exposed to on Earth.
• What are the two types of background radiation sources?

  • Natural sources
  • Man-made sources
• What is a natural source of background radiation mentioned in the material?


  Radon gas given off from some types of rock.
• What are some examples of natural sources of radiation that emanate every second?


  Rocks, cosmic rays from space, and foods.
• What are some examples of man-made sources of radiation?

  Fallout from nuclear weapons testing and exposure from medical testing.
• How does background radiation affect humans?


  It is the constant low-level radiation we are all exposed to on Earth every day.
• What is the role of cosmic rays in background radiation?

  Cosmic rays interact with the Earth's atmosphere sending showers of smaller particles down toward the Earth's surface.
• What is Cosmic Microwave Background Radiation (CMBR)?


  It is radiation from the Big Bang explosion that is still traveling across the Universe.
• How has CMBR changed over time?


  CMBR has been stretched out over time to the microwave region of the EM spectrum.
• What is the difference between background radiation and CMBR?


  Background radiation and CMBR are completely different phenomena.
• Why is it important to regulate human exposure to radiation?


  To protect against over-exposure to harmful radiation.
• How is the amount of radiation received by a person measured?


  It is measured in sieverts (Sv).
• What does one sievert represent in terms of radiation exposure?


  One sievert is a very big dose of radiation that would cause acute radiation poisoning.
• What is the average radiation dose a person receives in one year?


  About 3 mSv (0.003 Sv).
• What is a dosemeter used for?


  A dosemeter measures the amount of radiation in particular areas.
• How can a radiation badge help workers?


  A radiation badge can be worn to keep track of the amount of radiation they are receiving.
• How does a person's occupation or location affect their radiation exposure?

  • Some areas have higher background radiation due to proximity to sources.
  • People working with nuclear radiation receive more radiation.
• What is the UK limit for nuclear industry employees' radiation exposure in one year?


  20 mSv in one year.
• What is the radiation emitted by a banana considered?


  The amount of radiation within a banana is tiny and not at all dangerous.
• What unit measures the amount of radiation emitted by a source every second?

  Becquerels (Bq).
• What unit measures the rate at which radiation hits a particular location?

  Counts per second (cps).
• What does the term "half-life" refer to?


  The time it takes for the activity of a radioactive source to decrease to half of its original value.
• How do different radioactive isotopes vary in terms of half-lives?


  Different radioactive isotopes can have very different half-lives.
• What is the half-life of Francium-218?


  1 millisecond (0.001 seconds).
• What is the half-life of Polonium-210?


  About 140 days.
• What is the half-life of Uranium-235?


  About 700 million years.
• What happens if an isotope has a short half-life?


  The nuclei will decay very quickly, emitting a lot of radiation in a short amount of time.
• What is an advantage of using an isotope with a short half-life?


  It can quickly lose its radioactivity if only a small amount is used.
• What is a disadvantage of using an isotope with a large amount and a short half-life?


  The levels of radiation emitted could make handling the isotope extremely dangerous.
• What happens if an isotope has a long half-life?


  A sample will decay slowly and remain radioactive for a very long time.
• Why is radioactive waste with a long half-life buried underground?


  To prevent it from being released into the environment.
• What happens to the mass of a radioactive sample with each decay?


  The mass of the sample decreases with each decay.
• What occurs when an atom decays?


  It changes into another element; it doesn't disappear.
• How does the radiation emitted per decay differ between short and long half-lives?


  Substances with short half-lives emit more radiation per decay than substances with a long half-life.
• What is the relationship between decay frequency and radiation release for short half-lives?


  For short half-lives, the decays happen in quick succession, releasing radiation quickly.
• What are the medical uses of radiation?

  • Medical tracers: Track movement of substances in the body.
  • Radiotherapy: Treat cancer using radiation.
  • Sterilising medical equipment: Using gamma radiation for sterilisation.
• What is a medical tracer?


  A radioactive isotope used to track the movement of substances in the body.
• What type of radiation is usually used for medical tracers?


  Gamma emitters are usually used for this purpose.