Half-Life - GCSE Physics Definition

Half-life is the time taken for the number of radioactive nuclei in a sample to reduce by half. It is a measure of the rate of decay of radioactive substances and is a constant for each radioactive isotope. In practical terms, if you start with a certain amount of a radioactive isotope, half of it will have decayed after one half-life, reducing its radioactivity by 50%. It is a random process, which means it is not possible to predict which nuclei will decay next. Understanding the half-life of a radioactive isotope is crucial in fields like nuclear physics and helps with calculations related to radioactive decay.