When working in a laboratory with sources of ionizing radiation, safety regulations aim to minimize the radiation dose received by scientists.
Which of the following actions does not reduce a scientist's exposure or dose when handling an external radioactive source?
Selecting a source with a longer half-life but the same initial activity.
Using long-handled tongs to maximize the distance from the source.
Limiting the total time spent near the radioactive source.
Placing a lead shield of appropriate thickness between the source and the scientist.
484 exam-style questions on CIE IGCSE Physics 5.2 Radioactivity, covering 5.2.1 Background radiation and measuring count rate, 5.2.2a Alpha, beta and gamma emission, 5.2.2b Deflection and ionising effects of nuclear radiation, 5.2.3a Radioactive decay, 5.2.3b Effects of decay on the nucleus and decay equations, 5.2.4a Half-life, 5.2.4b Choosing isotopes for applications, and 5.2.5 Effects of ionising radiation and safety precautions. Each one has a worked solution and a mark scheme showing where the marks go.