🎯 Common Question Types:
- Determine half-life from graph (draw construction lines)
- Calculate activity after n half-lives
- Explain suitability of isotope for a given application
- Describe what happens to activity over time
📝 Key Command Words:
- Determine/Find: Use the graph — show construction lines
- Calculate: Show the halving chain step by step
- Explain: Give the reason linked to half-life value
- Suggest: Pick a half-life and justify it
⚠️ Common Mistakes to Avoid:
- Not drawing construction lines on graph — you lose method marks
- Thinking half-life = time for ALL material to decay (it never fully decays)
- Confusing activity (Bq) with count rate — they're proportional but not equal
- Forgetting to halve the activity, not the half-life, in calculations
This exam tips covers Exam Tips for 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 12 of 13 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
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
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.
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.