Physics 5054 · O Level · Radioactivity

Radioactivity — practice question

Table 10.1 gives information about the type and some properties of alpha, beta and gamma emissions. Fig. 10.1 shows surgical instruments sealed inside plastic bags, with the bags placed in thin plastic boxes. A conveyor belt carries the boxes near to a cobalt-60 source, which sterilises the instruments. The cobalt-60 source is a radioactive isotope of cobalt that gives out gamma-radiation. Fig. 10.2 shows an alpha-particle moving close to the nucleus of a gold atom.
(a)[6]

Fill in the missing information to complete Table 10.1.

(b(i))[2]

Describe what the term isotope means.

(b(ii))[1]

Suggest one property of gamma-radiation that allows it to sterilise the instruments inside the bagged boxes.

(b(iii))[1]

State why a source that emits only alpha-radiation cannot be used for this purpose.

(b(iv))[1]

The half-life of cobalt-60 is 5.3 years. Explain why a source whose half-life is 5.3 minutes would be unsuitable for this application.

(c(i))[2]

Explain why the alpha-particle is turned aside.

(c(ii))[2]

During the experiment, most of the alpha-particles go straight through the foil without being deflected. Explain, using ideas about atomic structure, why this occurs.

Worked solution & mark scheme

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