Chap 19 : Quantum Physics Flashcards
Photon
Quantum of electromagnetic radiation energy. Each quantum has energy equal to the product of Planck constant and the frequency of the electromagnetic radiation.
Photoelectric Effect
Emission of electrons from a metal surface when the surface is irradiated with electromagnetic radiation above the threshold frequency.
Threshold frequency
Minimum frequency of the incident radiation for electrons to be emitted from a metal surface irradiated with electromagnetic radiation.
Work function (energy) of a metal
Minimum amount of the energy necessary to remove an electron from the surface of the metal.
Stopping potential
Minimum retarding potential to stop all the electrons from reaching the collector plate.
Ground state
The ground state refers to the lowest energy configuration in which the atom is the most stable.
Excited state or excitation
Electron(s) in an atom are at the higher energy level(s) rather than at the lowest energy level(s).
De-excitation
An atom in an excited state is unstable and it will transit back to the lower energy states by emitting photon(s).
Ionisation energy
Energy required to remove an electron completely from the atom
Emission line spectrum
Series of distinct coloured lines against a dark background.
Absorption line spectrum
Series of distinct dark lines against a continuous spectrum.
