An experiment is carried out to investigate the absorption of radiation emitted from a radioactive source. The source and detector are placed approximately 2 cm apart in air, and a scaler is used to measure the count rate. Different absorbing sheets are placed in the gap between the source and the detector, yielding the following results:
| Absorbing material | Count rate (counts/s) |
|---|---|
| Air | 840 |
| Single sheet of paper | 840 |
| 1.0 mm of aluminium | 512 |
| 15 mm of aluminium | 247 |
| 20 mm of lead | 85 |
Explain how the data shows that the source does not emit α\alphaα-particles.
Describe the evidence indicating that β\betaβ-particles are emitted by the source.
Describe the evidence indicating that γ\gammaγ-rays are emitted by the source.
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.