alleryEstimate the drift speed of electrons in a copper wire carrying 1.5 A with cross-section 1.0×10⁻⁷ m² and n = 8.5×10²⁸ m⁻³ (e = 1.6×10⁻¹⁹ C):
A≈1.1×10⁻³ m s⁻¹
B≈1.1 m s⁻¹
C≈1.1×10⁻⁶ m s⁻¹
D≈3×10⁸ m s⁻¹
Answer & Solution
Correct answer: A. ≈1.1×10⁻³ m s⁻¹
v_d = I/(neA) = 1.5 / (8.5×10²⁸ × 1.6×10⁻¹⁹ × 1.0×10⁻⁷) ≈ 1.1×10⁻³ m s⁻¹ — only a few mm per second, showing drift is very slow.
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