This topic summary covers Topic Summary: Half-Life within Half-Life for GCSE Physics. Revise Half-Life in Atomic Structure for GCSE Physics with 13 exam-style questions and 23 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 13 of 13 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 13 of 13
Practice
13 questions
Recall
23 flashcards
Topic Summary: Half-Life
Key Terms
- Half-life: Time for activity to halve
- Activity: Decays per second (Bq)
- Becquerel (Bq): 1 decay per second
- Count rate: Detections per unit time
Key Facts
- Half-life is constant for each isotope
- Decay is random but statistically predictable
- Decay curve is exponential — never reaches 0
- Unaffected by temperature or pressure
Calculation Method
- Start → ÷2 → ÷2 → ÷2...
- Count halvings = number of half-lives
- n half-lives: activity × (½)ⁿ
- From graph: draw construction lines
Applications by Half-Life
- Medical tracers: hours
- Smoke detectors: years
- Carbon dating: 5,730 years
- Long half-life = long-term hazard