An aerospace engineer is calibrating a highly sensitive radiation detector designed for a CubeSat. Before testing, she ensures all radioactive calibration standards are locked away in a thick lead-shielded safe in a separate building. When she powers on the detector in the cleanroom, she observes that it still registers a low, steady rate of ionizing events.
Explain why the detector continues to register ionizing events despite the removal of all experimental radioactive sources.
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.