Quantum Phenomena Definitions Flashcards
Work Function
MINIMUM ENERGY needed to remove an electron from the SURFACE of a material
Work Function Units
joules
Threshold Frequency
MINIMUM FREQUENCY needed to remove an electron from the SURFACE of a metal
hf
photon energy
Φ
work function
Ek(max)
maximum kinetic energy of the released photoelectron
Electron Volt eV
the energy gained 1eV by an electron moved across a potential difference of 1V
Converting between eV and J
1eV=1.6x10^-19J
Excitation
An orbital electron moving up one energy level to another
Excited Atom
Atom in which an orbiting electron is raised up to a higher energy level
Ionisation (gas discharge tube)
when an electron is removed from an atom
Ionisation Energy
energy required to completely remove an electron from an atom in its ground state
Ground state of an atom
the lowest energy state of an atom
Fluorescence
high energy (UV) photons are absorbed and lower energy photons (with a longer wavelength) are emitted in the visible part of the spectrum
Wave Particle Duality
particles (photons, light) behave sometimes as particles and waves
Experiment showing waves behaving as particles
Photoelectric Effect
Experiment showing particles behaving as waves
Electron Diffraction
Momentum (p)
mass x velocity (p=mv)
Units of momentum
kg ms^-1
Stopping Potential
the potential difference needed to stop the fastest moving photoelectrons travelling with kinetic energy in the photoelectron effect
Ekmax= e x Vstopping
Particle Diffraction Effects
A particle will diffract when the sizeof the de Broglie wavelength is roughly the same size as the object causing the diffraction
