A safety and inspection company utilizes radioactive isotopes for two different monitoring devices.
In a domestic smoke alarm (Device 1), a small alpha-emitting source is placed a few millimetres away from a sensor inside a chamber.
For inspecting thick, double-walled industrial steel pipelines for blockages (Device 2), a scanner containing a gamma-emitting source is positioned on the outer surface of the pipeline with a detector on the opposite external side.
Explain why the alpha source in Device 1 must be positioned extremely close to the sensor inside the chamber, whereas the gamma source in Device 2 can be placed on the outside of the thick steel pipeline.
90 exam-style questions on Edexcel GCSE Physics 6.3 Nuclear equations and decay. Each one has a worked solution and a mark scheme showing where the marks go.