Drift Velocity And Resistance

Drift velocity and resistance cheat sheet

• Drift velocity:

• The average velocity of charge carriers under an applied electric field.

• SI unit: meters per second (m/s)

• Mobility:

• The drift velocity per unit electric field strength

• SI unit: square meter per volt-second (m2/Vs)

• Resistivity:

• Resistance of a conductor of unit length and unit cross-sectional area.

• SI unit: ohm-meter (Ωm)

• Ohm’s law:

• The current through a conductor is directly proportional to the voltage across it and inversely proportional to its resistance.

• SI units:

  • Current: Ampere (A)
  • Voltage: Volt (V)
  • Resistance: Ohm (Ω)

• Temperature dependence of resistivity:

• Metals: resistivity increases with temperature.

• Semiconductors: resistivity decreases with temperature.

• Superconductivity:

• Zero electrical resistance at a characteristic temperature (critical temperature).

• Requires cooling below the critical temperature.