A doctor injects a radioactive tracer into a patient. A camera outside the body detects the radiation from the tracer.
Why does the tracer emit gamma rays rather than alpha particles?
Gamma rays are more ionising, so they damage fewer body cells
Gamma rays have a longer half-life, so the scan can last longer
Gamma rays are stopped by skin, so they stay inside the organ
Gamma rays pass out of the body, so they can reach the camera
48 exam-style questions on OCR GCSE Physics 6.2 Uses and hazards, covering 6.2.1 Contamination and irradiation, 6.2.2 Half-life and radiation hazards, 6.2.3 Medical uses of nuclear radiation, 6.2.4 Nuclear fission and chain reactions, and 6.2.5 Nuclear fusion. Each one has a worked solution and a mark scheme showing where the marks go.