15.5.A.1 The photoelectric effect is the emission of electrons when electromagnetic radiation is incident upon a material.
15.5.A.2 The emission of electrons via the photoelectric effect requires a minimum frequency of incident light, called the threshold frequency.
15.5.A.2.i Light that is incident on a material at the threshold frequency or higher will induce electron emission, regardless of the number of photons that strike the material.
15.5.A.2.ii The energy of the emitted electrons is not dependent on the number of photons that are incident upon the material, which provides evidence that light is a collection of discrete quantized energy packets called photons.
15.5.A.3 The maximum kinetic energy of an emitted electron is related to the frequency of the incident light and the work function of the material.
15.5.A.3.i The work function of a material is the minimum energy required to emit an electron from atoms within the material.
15.5.A.3.ii The maximum kinetic energy of an emitted electron is given by the equation
15.5.A.4 Stopping potential is the minimum applied electric potential difference that stops the flow of electrons.
15.5.A.4.i For applied potential differences less than the stopping potential, an electron is able to be emitted.
15.5.A.4.ii The stopping potential is proportional to the maximum kinetic energy of ejected electrons.