This definitions covers Key Definitions 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 7 of 13 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
📖 Key Definitions
Half-life: The time taken for the number of radioactive nuclei in a sample (or the activity of the sample) to halve.
Activity: The number of nuclear decays per second, measured in becquerels (Bq). 1 Bq = 1 decay per second.
Count rate: The number of radiation counts detected per unit time (often per minute or second). Related to, but not equal to, activity.
Becquerel (Bq): The SI unit of radioactivity. 1 Bq = 1 nuclear decay per second.
Practice questions for Half-Life
What is the definition of half-life?
Explain what is meant by saying radioactive decay is 'random and spontaneous'.