An archaeologist is using a Geiger-Müller (GM) counter to measure the radioactivity of an ancient glazed pottery shard.
She holds the detector in a fixed position close to the shard and records the readings shown in the table below.
| Time (minutes) | Detector reading (counts/minute) |
|---|---|
| 0 to 1 | 34 |
| 1 to 2 | 29 |
| 2 to 3 | 35 |
| 3 to 4 | 31 |
| 4 to 5 | 33 |
| 5 to 6 | 28 |
Explain the fluctuations in the detector readings.
The glaze on the pottery shard contains a radioisotope that emits both α\alphaα-particles and β\betaβ-particles. To handle the shard, the archaeologist wears thick safety gloves made of dense rubber.
Explain why wearing these gloves provides some protection from the radiation, but is not sufficient for complete safety.
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.