Radioactivity Flashcards
Define: radiation
the emission of energy either as wave or particle
Define: background radiation
ionising radiation in our environment which can be natural or artificial
Define: ionising radiation
has enough energy to ionise (remove an electron from an atom), which can change the chemical composition of the material
Define: non-ionising radiation
has enough energy to excite molecules and atoms, causing them to vibrate faster
List 3 sources of natural background radiation
Isotopes in rocks, plants and animals, cosmic rays
List 3 sources of artificial background radiation
medical procedures, nuclear power or weapons, industrial sterilisation or gauging devices
Define: isotope
Atoms of the same element with varying amounts of neutrons, leading to different atomic weights.
Define: radioisotope
isotopes emitting radiation to achieve a more stable form
Define: half-life
the amount of time it take for a radioisotope to decay in half
List the types of nuclear decay
alpha (α), beta (β), gamma (γ)
Describe alpha radiation
2 neutrons, 2 protons (equivalent to a helium nuclei)
Describe beta radiation
1 electron
Describe gamma radiation
electromagnetic particle
Describe the penetration depth of alpha radiation
Stopped by paper or a few centimetres of air
Describe the penetration depth of beta radiation
Stopped by a few millimetres of aluminium
Describe the penetration depth of gamma radiation
Stopped by centimetres of lead or metres of concrete
Describe the ionising energy of alpha radiation
Strongly ionising
Describe the ionising energy of beta radiation
Weakly ionising
Describe the ionising energy of gamma radiation
Very weakly ionising
State the formula for the quantity of remaining radioactive substance
remaining atoms = original quantity * (1/2)^(time passed/half-life)
