Year 12 - EM Radiation and Quantum Flashcards
Absorption spectrum
In absorption electron becomes excited/moves to higher energy state/level (by absorbing photon). This shows as black lines on a continuous spectrum.
de Broglie Hypothesis
(All matter particles) have a wave-like nature/wave-like properties.
de Broglie Wavelength
The wavelength (λ) of a particle in relation to its velocity and mass. The de Broglie Wavelength is inversely proportional to a particles momentum.
De-Excitation/Relaxation
De-excitation demotes an (orbital) electron from a higher energy level to a lower energy level. A photon is emitted with energy equal to the difference in energy levels.
Duality of Electrons
Electrons can have both wavelike properties and particle like properties.
Duality of Particles, Examples
Wave-like nature: Electron Diffraction.
Particle-like nature: Charged particles turning in a Magnetic Field or Particle Collisions.
Duality of Waves, Examples
Wave-like nature: Wave Interference.
Particle-like nature: Photoelectric Effect.
Electron Volt
The energy that an electron gains when it is accelerated through a potential difference of 1 volt.
Emission spectrum
In emission electron de-excited/moves to lower energy state (by emitting photon). This shows as discreate wavelengths of light that correspond to the difference in energy levels. Light is emitted.
Energy Level
Atoms contain discrete quantised energy levels at which electrons can exist. An electron cannot exist between energy levels. They can only move from one discrete energy level to another.
Excitation
Electron receives (exactly the right amount of) energy, excitation promotes an (orbital) electron to a higher energy/up a level.
Fluorescent tube
Accelerated Electrons collide with the Electrons in the Mercury Vapour exciting them to higher energy levels. These Electrons then de-excite/relax and emit ultraviolet. The coating of the tube absorbs UV light from the gas and emits visible light.
Ground State
When electrons/atoms are in their lowest/minimum energy (state) or most stable (state) they (are in their ground state).
Ionisation
Ionisation occurs (when an electron receives enough energy) to leave the atom.
Ionisation Energy
The minimum amount of energy required to release an electron from the ground state.
Photoelectric Effect
The release of (photo) electrons from a (metal) surface when electromagnetic radiation is incident on the surface.
Photoelectron
An electron that has been emitted by incident light on a metal surface due to the photoelectric effect.
Photon
The smallest possible packets of electromagnetic energy.
Stopping Potential
The minimum potential that is applied to the metal surface to reduce the photoelectric current to zero when monochromatic light is incident on the surface.
Threshold Frequency
The minimum frequency of an incident photon required to remove an electron from the surface of a metal.
Wave-Particle Duality
That particles and waves can display both particle and wavelike properties.
Work Function
Minimum energy required to remove an electron from a (metal) surface.
