AQA · GCSE · Physics
Course version: 8463 · Version from Sept 2016
Suitable precautions must be taken to protect against any hazard that the…
Full specification wording
Radioactive contamination: Suitable precautions must be taken to protect against any hazard that the radioactive source used in the process of irradiation may present.
Anything used to irradiate an object is itself a radiation source, so the people nearby must be protected.
Checked against the AQA 8463 specification (opens in a new tab) on .
- Point 7 of 8
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Anything used to irradiate an object is itself a radiation source, so the people nearby must be protected. Three controls do the work. Reduce time: return the source to its lead-lined box between measurements rather than leaving it out. Increase distance: handle sources with long tongs, hold them at arm's length and point them away from people, since the radiation spreads out and the dose falls with distance. Add shielding: lead or thick concrete for gamma, a few millimetres of aluminium for beta. Sealed sources and gloves add protection against contamination as well, which matters because gloves prevent transfer of radioactive material even though they do not stop the hands being irradiated. Workers wear film badges to monitor the dose they accumulate.
What earns the marks
- A named precaution that increases distance, such as using long tongs or holding the source at arm's length.
- A precaution that reduces exposure time, such as returning the source to a lead-lined box between readings.
- Named shielding matched to the radiation, lead or concrete for gamma.
- Gloves or a sealed source preventing transfer of radioactive material as well as limiting irradiation.
Common mistakes and how to put them right
Giving a vague precaution such as 'be careful' or 'follow the safety rules', which earns nothing.
Saying a lab coat or safety goggles stop gamma radiation.
Claiming gloves reduce the irradiation of the hands.
Naming paper as shielding for a gamma source.
Offering only one precaution when the question asks for two.
Exam tips
- Pick precautions from different categories, one for time, one for distance and one for shielding, so they cannot be read as the same point twice.
- Match the shielding to the radiation named in the question; lead for an alpha source is not credited as good practice.
- Say what the precaution achieves, not just what it is, because the reason often carries the second mark.
Try the lesson
The start of the Radioactive contamination: Suitable precautions must be taken to protect against any hazard that the radioactive source used in the process of irradiation may present. lesson, made from checked teaching notes for this specification point.
Have a go first
Which of the following is a suitable precaution to take when using a radioactive source for an irradiation experiment in a school laboratory?
Listen
Anything used to irradiate an object is itself a radiation source, so the people nearby must be protected. Three controls do the work. Reduce time: return the source to its lead-lined box between measurements rather than leaving it out. Increase distance: handle sources with long tongs, hold them at arm's length and point them away from people, since the radiation spreads out and the dose falls with distance. Add shielding: lead or thick concrete for gamma, a few millimetres of aluminium for beta. Sealed sources and gloves add protection against contamination as well, which matters because gloves prevent transfer of radioactive material even though they do not stop the hands being irradiated. Workers wear film badges to monitor the dose they accumulate. A strong answer earns marks for these points. a named precaution that increases distance, such as using long tongs or holding the source at arm's length. a precaution that reduces exposure time, such as returning the source to a lead-lined box between readings. named shielding matched to the radiation, lead or concrete for gamma. gloves or a sealed source preventing transfer of radioactive material as well as limiting irradiation. Exam tip: Pick precautions from different categories, one for time, one for distance and one for shielding, so they cannot be read as the same point twice.
See it
Key words
Say what each word means before you turn the card.
time distance shielding
Try answering aloud or in your head before turning the card.
lead-lined storage
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handling with tongs
Try answering aloud or in your head before turning the card.
sealed sources
Try answering aloud or in your head before turning the card.
See every definition
- time distance shielding
- Three controls that protect people nearby: reduce time, increase distance and add shielding.
- lead-lined storage
- Returning the source to its lead-lined box between measurements rather than leaving it out.
- handling with tongs
- Using long tongs to handle sources, holding them at arm's length and pointing them away from people.
- sealed sources
- Sources that add protection against contamination as well as limiting irradiation.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
3Box 3
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