quantum physics Flashcards
photon!!!
a discrete bundle/quantum of electromagnetic radiation energy.
each quantum has energy equal to the product of the Planck constant and the frequency of electromagnetic radiation
photoelectric effect
the emission of electrons from a metal surface when the surface is irradiated with electromagnetic radiation above the threshold frequency
threshold frequency
the minimum frequency of the incident radiation for electrons to be emitted from a metal surface irradiated with electromagnetic radiation
work function (Φ)
minimum amount of energy necessary to remove an electron from the surface of a metal
stopping potential (Vs)
minimum retarding potential to stop all the electrons from reaching the collector plate.
ground state
lowest energy configuration in which the atom is the most stable
excited state/excitation
electrons in an atom are at the higher energy levels rather than at the lowest energy levels.
de-excitation
an atom in an excited state is unstable, and will transit back to the lower energy state by emitting photons
ionisation energy (NOT CHEM)
energy required to remove an electron completely from the atom
emission line spectrum (ELS)
series of distinctly coloured lines against a dark background
light of certain wavelengths are emitted by hot gas as EMR, thus causing only certain frequency lines to be present
absorption line spectrum
series of dark lines against a continuous spectrum
light of certain wavelengths are absorbed by cool gas as EMR. unabsorbed wavelengths of light appear darker when photons are radiated in all directions
Bremsstrahlung (continuous X-ray spectrum)
when electrons are accelerated, EMR is produced. the wavelength of the photon depends on the magnitude of acceleration. as the incident electrons experience a distribution of photos, a continuous spectrum is formed
heisenberg momentum-uncertainty principle (how to get the formula)
the more precisely the position of a particle is determined, the less precisely its momentum can be known => ΔpΔx>=h
X-ray peaks
electrons incident on the metal collide and knock of electrons from the inner K shell, leading to de-excitation of electrons within the target atoms
