E.3.12—Half-life changes Topic Practice
E.3.12—Half-life changes Topic Practice
Practise predicting how much remains after several half-lives and converting fractional changes in activity, mass or nuclei into elapsed time.
How this is tested
- recognise fractions like 1/8 remaining or 7/8 decayed as whole numbers of half-lives before calculating time
- compare two nuclides by counting elapsed half-lives to find numbers of atoms or a ratio still undecayed
- use either repeated halving or A=A0e^-lambda t to determine the remaining mass or nuclei after a stated time