H2 Physics 15 - Currents: Drift Velocity in a Current-Carrying Wire

What you will learn

• Copper wire with A = 1.5 x 10^-6 m^2 carrying I = 3.0 A; free-electron density n = 8.5 x 10^28 per m^3.
• Microscopic current relation: I = n A v e; rearrange to v = I / (n A e).
• Drift velocity v is about 1.5 x 10^-4 m/s, or 0.15 mm/s.