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Physics Paper 1 · P4 · Lesson 4.11

Higher Tier: half-life ratios

Optional Higher Tier work: distinguish what remains from what has decayed.

Key ideas1 of 3

Higher Tier: the fraction remaining

After each half-life, halve the amount remaining.
1 → 1/2 → 1/4 → 1/8.
After 3 half-lives, remaining : initial is 1 : 8.

Higher Tier: fraction remaining is 1 initially, 1/2 after one half-life, 1/4 after two, and 1/8 after three.

Higher Tier only. First be confident with the core half-life lesson.

Next: Higher Tier exam practice →
Topic resources and sources

Daily 5 · Core exam practice · Higher Tier questions · A4 revision sheet

Lessons 4.1–4.10 cover the core. Lesson 4.11 is Higher Tier only. Daily 5 practises core facts. Answer positions are shuffled on each new attempt; lessons begin with very simple questions.

AQA Combined Science Trilogy specification · 6.4.2.3 · Higher Tier only. Original notes, questions and diagrams. Experimental numbers are illustrative.

Photos: Geiger counter by Boffy b, enhanced by Marco Plassio; caesium source by Wusel007, enhanced by Partynia, both CC BY-SA 3.0. Rutherford at McGill, 1905, unknown photographer / Wellcome Images, public domain. Photos displayed without cropping or other alterations.