AQA GCSE Physics revision questions on Half-lives and the random nature of radioactive decay

A few short questions here and a few videos to watch. Specification page 40

1. Copy and complete: Radioactive decay is _____________. 
2. Copy and complete this paragraph: The half-life of a radioactive isotope is the time it takes for the number of __________ of the isotope in a _________________, or the time it takes for the count rate (or activity) from a sample containing the isotope to fall to half its ________________. 
3. Watch these videos which tell you how to calculate half-life. https://www.youtube.com/watch?v=zXw2cOSBB8E and https://www.youtube.com/watch?v=wj9BzGFao8k&t=1s. 

Audio Answers