A student uses a Geiger-Müller counter to detect the radiation from a sample of uranium ore in a physics laboratory. The teacher explains that they must first measure and subtract the background radiation.
What is this background radiation?
ultraviolet light from the laboratory's ceiling lights
ionising radiation present in the laboratory when the uranium ore is not there
infrared radiation emitted by the student and the laboratory equipment
radio waves from nearby communication transmitters
44 exam-style questions on CIE IGCSE Physics 5.2.1 Background radiation and measuring count rate. Each one has a worked solution and a mark scheme showing where the marks go.