Ch23 Radioactivity Flashcards
Define radioactive substance:
Substance that decays by emitting radiation from its atomic nuclei
Define radiation:
Energy spreading out from a source carried by particles/waves
Define contaminated:
When an object has acquired some unwanted radioactive substance
Define irradiated:
When an object has been exposed to radiation
Define background radiation:
The radiation from the environment to which we are exposed all the time
Define count rate:
The number of decaying radioactive atoms detected each second (or minute, or hour)
Define radioactive decay:
The emission of alpha, beta or gamma radiation from an unstable nucleus
Define random process:
A process that happens at a random rate and in random directions; the timing and direction of the next emission cannot be predicted
Define beta particle (β-particle):
A high-speed electron that is emitted by an atomic nucleus during radioactive decay
Define gamma ray ( γ-ray)
Electromagnetic radiation emitted by an atomic nucleus during radioactive decay
Define ionising nuclear radiation:
Radiation, emitted by the nucleus which can cause ionization;
Alpha/beta particles/gamma rays
Define radioisotope:
A radioactive isotope of an element
Define alpha decay:
The decay of a radioactive nucleus by the emission of an α-particle
Define beta decay:
The decay of a radioactive nucleus by the emission of a β-particle
Define activity:
The rate act which nuclei decay in a sample of a radioactive substance
