Y1 Ch 03 Definitions Flashcards
Quantum of energy
a small packet of energy
Photon
the name given to a quantum of light.
Electron Volt
a unit of energy equal to 1.6*10^-19 J.
Energy Levels
Levels of energy that electrons with a certain amount of energy occupy.
Ground State
When electrons are in there lowest energy level.
Excitation
When an electron in an atom moves up an energy level after it has absorbed energy.
Ionisation
When an atom gains or loses an electron and becomes charged.
Ionisation energy
The energy required to move an electron from its ground state to infinity i.e. to become detached from the atom.
Diffraction grating.
a piece of transparent material ruled with very closely spaced lines, used to see the diffraction of light.
Continuous spectrum
A spectrum where all frequencies of radiation or colours of light are possible.
Line spectrum
a spectrum of discrete coloured lines of light
Emission Spectrum
A bright spectrum seen when photons are emitted by atoms.
Absorption Spectrum
A spectrum of dark lines seen on a coloured background produced when a gas absorbs photons
Fluorescence
when a substance absorbs short wavelength electromagnetic radiation and emits it as longer wavelength radiation.
A Fluorescent Tube
a type of light bulb that gives out light when it’s inner coating fluoresces
