ELM-006 · Direct current Sample material

The nature of electrical conductivity in metals

The nature of current carriers in metals: the Riecke, Mandelstam–Papaleksi and Stewart–Tolman experiments, the Drude–Lorentz classical electron theory, derivation of Ohm's and Joule–Lenz laws, difficulties of the theory and superconductivity.

Estimated time: 3 h 4 activities

Learning objective

Explain the experiments proving that current carriers in metals are electrons.
Derive Ohm's and Joule–Lenz laws from the classical electron theory.
Master the concepts of drift velocity, mean free time and mean free path.
Become acquainted with the limits of the classical theory and the phenomenon of superconductivity.

Expected outcomes

Can calculate the drift velocity of electrons and the free-electron concentration in a metal.
Can estimate the mean free time and path from the resistivity.
Can find the ratio e/m from the results of the Stewart–Tolman experiment.
Can explain the main properties of superconductors (Tc, Meissner effect, critical field) and their applications.

Interactive modelElectron drift in a metal

Activities

Lecture
Lecture · 1 h 20 min · required
Solving problems on the nature of electrical conductivity
Practice · 1 h 20 min · required
Superconductors and their nature
Self-study · 6 h · optional
Final test
Test · 20 min · required · pass ≥ 70%

Completion conditions

  • Lecture
  • Solving problems on the nature of electrical conductivity
  • Final test — at least 70%