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Drift speed of electrons, 10 A

Short answer

Drift speed v_d = I/(nAe). With I = 10 A, A = 1×10⁻⁶ m², n = 8.5×10²⁸ m⁻³, e = 1.602×10⁻¹⁹ C, v_d ≈ 7.3×10⁻⁴ m/s (0.73 mm/s).

Calculate the drift speed of electrons when 10 A current is supplied through a copper wire of cross sectional area 1 mm² and electron density 8.5×10²⁸ m⁻³.

Using I = n A e v_d, v_d = I/(nAe).

Given: I = 10 A, A = 1 mm² = 10⁻⁶ m², n = 8.5×10²⁸ m⁻³, e = 1.602×10⁻¹⁹ C.

n A e = 8.5×10²⁸ × 10⁻⁶ × 1.602×10⁻¹⁹ = 1.3617×10⁴ C/m
v_d   = 10 / 1.3617×10⁴
      = 7.34×10⁻⁴ m/s

Answer: v_d ≈ 7.3×10⁻⁴ m/s ≈ 0.73 mm/s

✓ Answer checked by Claude Opus 5.5 (high effort)

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