| Application | Half-life needed | Why? |
|---|---|---|
| Medical tracers | Hours | Long enough to detect, short enough to not harm patient |
| Smoke detectors | Years | Needs to last lifetime of detector |
| Carbon dating | 5,730 years | Suitable for dating things thousands of years old |
| Nuclear waste | Varies | Long half-lives = storage problem for thousands of years |
This key facts covers Uses Based on Half-Life within Half-Life for GCSE Physics. Revise Half-Life in Atomic Structure for GCSE Physics with 15 exam-style questions and 23 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 5 of 13 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Half-Life
What is the definition of half-life?
Explain what is meant by saying radioactive decay is 'random and spontaneous'.
Quick recall flashcards
What is half-life?
Half-life is the time taken for half the unstable nuclei in a radioactive sample to decay, or the time for the activity of a radioactive source to fall to half its original value.
Why is radioactive decay described as random?
Radioactive decay is random because we cannot predict when any individual nucleus will decay. We can only predict the probability of decay and the average behaviour of large numbers of nuclei.