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The Photoelectric Effect

AQA AS-level PhysicsTopic 4 of 1419 lessons

Revision notes for The Photoelectric Effect in AQA Physics (7407). Every lesson in BrainCake comes with R.E.C.I.P.E. recall steps, a quick check and spaced reviews.

  1. The Photoelectric EffectWhen electromagnetic (EM) radiation above a certain frequency is directed at the surface of a metal electrons are emitted from the surface.
  2. Explanation of the Photoelectric EffectLight is composed of photons (wave packets) h = Planck constant 6.63 × 10-34 Js One electron at the surface of the metal absorbs a single photon.
  3. The Stopping PotentialStopping Potential Vs If the metal is given a sufficient positive charge electrons that escape are attracted back.
  4. Planck's Quantum TheoryConduction electrons move about at random.
  5. The Vacuum PhotocellA glass tube that contains a metal plate (photocathode) and a smaller metal electrode (anode).
  6. IonisationIons are formed from an uncharged atom by adding or removing electrons. α, β and γ radiation create ions when they pass through matter and collide…
  7. Measuring Ionisation EnergyElectrons are emitted from a heated filament in a sealed tube and are attracted to a positive anode.
  8. Energy of ElectronsThe electron volt is a unit of energy equal to the work done when one electron is moved through a potential difference of 1 volt 1 eV = 1.6 × 10-19…
  9. Electron Excitation by CollisionsWhen gas particles collide with electrons if there is not enough energy for ionisation at certain energies excitation occurs.
  10. Excitation Using PhotonsWhen an electron absorbs a photon it gains enough energy to move into an outer shell where a vacancy exists if the energy of the photon is equal to…
  11. De-excitationThe excited state of the electron is unstable.
  12. FluorescenceAtoms that absorb u.v. light and become excited are able to emit visible light when they de-excite.
  13. Fluorescent TubeA fluorescent tube is a glass tube with a fluorescent coating on its inner surface containing mercury vapour at low pressure.
  14. Line SpectraWhen the light from a hot gas is passed through a prism or diffraction grating, it forms a line spectrum: a set of sharp coloured lines at…
  15. Excitation of Hydrogen AtomsThe simplest atom is hydrogen.
  16. The Discovery of HeliumHelium was discovered from the light spectrum of the Sun.
  17. The Dual Nature of LightLight has a dual nature.
  18. De Broglie's HypothesisLike light, matter also has a wave-particle dual nature.
  19. Evidence for de Broglie's HypothesisEvidence for the de Broglie Hypothesis consists of a narrow beam of electrons directed at a thin metal foil.

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