Radioactive decay, which can involve the emission of alpha (α\alphaα), beta (β\betaβ), or gamma (γ\gammaγ) radiation, is characterized as being both random and spontaneous.
Which row in the table correctly describes the meaning of these two terms?
| Random | Spontaneous | |
|---|---|---|
| A | The decay rate is unaffected by external factors, such as temperature and pressure. | It is impossible to predict which nucleus will decay next or precisely when a given nucleus will decay. |
| B | It is impossible to predict which nucleus will decay next or precisely when a given nucleus will decay. | The decay rate is unaffected by external factors, such as temperature and pressure. |
| C | Particles are emitted in all directions with equal probability. | The process happens instantly without any time delay. |
| D | The decay process is triggered by a random collision with a cosmic ray. | The decay occurs without any external trigger or change in physical conditions. |
Row A
Row B
Row C
Row D
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.