Uses and dangers of radiation

• Irradiation is the process of exposing an object to a source of radiation.
• Radioactive sources can be very useful but need handling carefully to ensure safety.
• Exposing objects to beams of radiation is called irradiation.
• The term applies to all types of radiation including radiation from the nuclei.
• The nucleus is the central part of an atom.
• An atom consists of a nucleus containing protons and neutrons, surrounded by electrons.
• Irradiation from radioactive decay is the process in which unstable atomic nuclei break apart or change, releasing radiation as they do so.
• Irradiation can damage living cells.
• Irradiation can be used to preserve fruit sold in supermarkets by exposing the fruit to a radioactive source - typically cobalt-60.
• The gamma ray, the shortest wavelength and highest energy part of the EM spectrum, is produced by radioactive materials and is emitted by the cobalt.
• Gamma rays will destroy any bacteria on the fruit but will not change the fruit in any significant way.
• The process of irradiation does not cause the irradiated object to become radioactive.
• Advantages of irradiation include sterilisation can be done without high temperatures it can be used to kill bacteria on things that would melt.
• Disadvantages of irradiation include it may not kill all bacteria on an object it can be very harmful - standing in the environment where objects are being treated by irradiation could expose people’s cells to damage and mutation.
• Contamination is the presence of unwanted substances in a product or environment.
• Models of the atom - AQA
• Atoms, isotopes and ions - AQA
• Radioactive decay - AQA
• Sample exam questions - atomic structure - AQA
• Related links Combined Science Exam practice
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