Surgical instruments in sealed plastic bags are placed in thin plastic boxes. A conveyor belt takes the boxes close to a cobalt-60 source which sterilises the instruments.
This is shown in Fig. 10.1.
Fig. 10.1 (viewed from above)
The cobalt-60 source is a radioactive isotope of cobalt that emits gamma-radiation
(i)
Describe what is meant by the term isotope.
[2]
(ii)
Suggest a property of gamma-radiation that enables it to sterilise the instruments in the bags in the boxes.
[1]
(iii)
State why a source emitting only alpha-radiation cannot be used in this way.
[1]
(iv)
The half-life of cobalt-60 is 5.3 years.
Explain why a source with a half-life of 5.3 minutes is unsuitable for use in this application.
[1]