In an experimental setup, a radioactive source is directed towards a radiation detector. With a thin sheet of paper placed between the source and the detector, the detector continues to show a reading significantly higher than the background level. When the paper is replaced by a 5 mm thick aluminium sheet, the reading on the detector falls to the background level. Which type of radiation is being emitted by the source?
α\alphaα-radiation
β\betaβ-radiation
γ\gammaγ-radiation
X-ray\text{X-ray}X-ray radiation
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.