The Random Nature of Nuclear Decay
- Radioactive decay is defined as:
The spontaneous disintegration of a nucleus to form a more stable nucleus, resulting in the emission of an alpha, beta or gamma particle
- The random nature of radioactive decay can be demonstrated by observing the count rate of a Geiger-Muller (GM) tube
- When a GM tube is placed near a radioactive source, the counts are found to be irregular and cannot be predicted
- Each count represents a decay of an unstable nucleus
- These fluctuations in count rate on the GM tube provide evidence for the randomness of radioactive decay
The variation of count rate over time of a sample radioactive gas. The fluctuations show the randomness of radioactive decay
- Radioactive decay is both spontaneous and random
- A spontaneous process is defined as:
A process which cannot be influenced by environmental factors
- This means radioactive decay is not affected by environmental factors such as:
- Temperature
- Pressure
- Chemical conditions
- A random process is defined as:
A process in which the exact time of decay of a nucleus cannot be predicted
- Instead, the nucleus has a constant probability, i.e.. the same chance, of decaying in a given time
- Therefore, with large numbers of nuclei, it is possible to statistically predict the behaviour of the entire group
Examiner Tip
Make sure you can define what constitutes a radioactive decay, a random process and a spontaneous decay - these are all very common exam questions!
