Quantum physics definitions Flashcards
Photoelectric effect
A process in which electrons are emitted from a metal surface when electromagnetic radiation of sufficiently high frequency is incident on the surface
Photoelectron
An electron emitted from the surface of a material due to the incident electromagnetic radiation
Stopping potential
The magnitude of the negative potential of collector with respect to emitter which prevents the most energetic photoelectrons from reaching the collector and hence resulting in zero photocurrent
Photon
A quantum of electromagnetic energy
Work function
The work function energy of a metal is defined as the minimum amount of energy necessary for an electron to escape from the surface of a material
Threshold frequency
The minimum frequency of electromagnetic radiation below which no emission of photoelectrons occurs
Wave-particle duality
The theory where matter and waves have particle-like and wave-like characteristics
De Broglie wavelength
The wavelength associated with wave-like properties of a particle
Heisenberg uncertainty principle
If a measurement of the position of a particle is made with uncertainty delta x and a simultaneous measurement of its x-component of momentum is made with uncertainty delta p, the product of the two uncertainties can never be smaller than h bar / 2
Bremsstrahlung X-ray
The broad spectrum, high energy EM radiation produced when highly energetic electrons are decelerated
Characteristic X-ray
The sharp spectrum, high energy EM radiation produced when electrons from a higher shell de-excite to a vacancy in the lower-shell, created by highly energetic electrons
Threshold wavelength
The maximum wavelength of EM wave to cause photoemission
Absorption line spectra
Dark spectral lines on continuous bright background obtained when white light illuminating a cool vapour passes through a diffraction grating
Emission line spectra
Bright spectral lines on dark background obtained when EM radiations emitted by diffuse gas (excited by heat or electric discharges) pass through a diffraction grating
Ground state
The lowest and most stable energy state of an atom
