4.5 Quantum

• What is the photoelectric effect

  The emission of electrons from a metal surface when electromagnetic radiation is incident on the surface of the metal.
• How can the photoelectric effect be shown

  • A clean zinc plate initially charged
  • Source of illumination with different intensities and frequencies
  • Gold leaf electroscope to show if a charge is present
• What predictions does wave theory make

  • All frequencies cause emission, provided the source is sufficiently intense to remove electrons
  • Greater intensity results in faster emission, due to the rate of energy transfer being quicker
  • Frequency does not affect emission, due to frequency not effecting energy
  • Greater intensity results in greater kinetic energy in the electrons