A teacher carries out two experiments at the same time.
In the first experiment, the count rate for a sample of a radioactive isotope is measured every hour for 9 hours. The results are shown in the table below:
| Time (hours) | Count rate (counts/second) |
|---|---|
| 0.0 | 1605 |
| 1.0 | 1274 |
| 2.0 | 1012 |
| 3.0 | 802 |
| 4.0 | 637 |
| 5.0 | 506 |
| 6.0 | 401 |
| 7.0 | 318 |
| 8.0 | 253 |
| 9.0 | 200 |
Estimate the half-life of the radioactive isotope. Use the information in the table.
half-life=.................................................... hours \text{half-life} = \text{.................................................... hours} half-life=.................................................... hoursIn the second experiment, the teacher repeats the procedure with another sample of the same radioactive isotope. The mass of the second sample is smaller than that of the first sample.
Suggest a value for the count rate for this sample at the start of the experiment.
count rate=.................................................... counts/second \text{count rate} = \text{.................................................... counts/second} count rate=.................................................... counts/secondOne type of particle emitted during radioactive decay is a β\betaβ-particle (beta/beta-minus particle).
Describe:
the nature of a β\betaβ-particle
the ionising ability of a β\betaβ-particle
the penetrating ability of a β\betaβ-particle.
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.