What half-life means
What half-life means
Half-life is the time taken for half the undecayed nuclei in a radioactive sample to decay. Equivalently, it is the time taken for the activity or count rate of a source to fall to half its starting value.
Step-by-step lessons on Edexcel GCSE Physics 6.4 Half-life. Each one builds up to exam-style questions. Master the required practical work and core equations early, since both papers can draw on content and maths skills from across the whole specification.