Spectra Flashcards
Bohr Model
A model of the atom with a central positive nucleus and electrons in definite energy levels surrounding the nucleus
Energy Level
An electron orbit inside the Bohr atom
Ground state
The lowest permitted energy level in an atom
Ionisation level
The energy level at which an electron escapes from the electric field of the nucleus
Irradiance
The power per unit area of a radiation
Line spectra
Lines with certain frequencies emitted by an element
Photoelectric effect
Electrons are emitted from solids, liquids and gases when they absorb energy from light
Photoelectron
An electron ejected from a material by the photoelectric effect
Photon
A quantum of electromagnetic radiation
Plancks constant
The constant of proportionality between the energy of a phot n and its frequency
Point source
Where the light from a point spreads out evenly in all directions
Threshold frequency
The minimum frequency of a photon which causes electron emission
Work function
The minimum energy required to eject an electron from its parent atom
Zero potential energy
An electron has zero potential energy in a nucleus’ field when it has escaped from the field. This happens when ionisation takes place.
Absorption Spectra
Black lines in a continuous spectrum caused when the vapour of an element absorbs particular photons of light. The photons absorbed have exactly the same energy as energy gaps in the energy level within the elements atom.
