Loading…
Loading…
GCSE Physics · key term
Exposure of an object or person to ionising radiation from a source, without radioactive material being transferred to them.
Used by AQA, Edexcel and OCR
Specification 4.4.2.4 · Paper 1
The process of exposing an object to nuclear radiation from an external source; the irradiated object does not become radioactive.
Revise: Radioactive contaminationTwo situations must be distinguished carefully: contamination, in which radioactive atoms are somewhere they are not wanted, and irradiation, in which radiation reaches an object from a source outside it.
Specification 6.28P, 6.32 · Paper 1
Exposure of an object or material to radiation from a source; the source itself is not transferred.
Specification P6.2a · Paper 2 (Foundation), Paper 4 (Higher)
Exposure of an object or living thing to radiation from a source.
Revise: Contamination vs irradiationIrradiation happens when that radiation reaches an object or person. The source can remain separate: for example, a sealed radioactive source may irradiate someone's hand without any radioactive material getting onto it. Moving away from the source stops that exposure, although any damage already caused by the radiation does not simply disappear.
Paper 1, Paper 2
Exposure to radiation emitted by a source, without radioactive material necessarily being transferred.
Revise: Contamination and IrradiationIrradiation means radiation from a source reaches an object or person. For example, skin is irradiated while a sealed source nearby emits radiation towards it. Moving away from or shielding the source ends that exposure.
Use the words radioactive material when describing contamination, but radiation from an external source when describing irradiation.
In a comparison, state both how exposure occurs and when it stops: contamination can continue while the atoms remain; irradiation stops when the source is removed or shielded.
Do not say that irradiation normally makes an object radioactive. The AQA specification states that the irradiated object does not become radioactive.
Create a free account to read GCSE Physics revision notes for your exam board and track your progress.