Home › AP Intermediate 2nd Year › Physics › Current Electricity › Estimate the drift speed of electrons in a coppe…
Estimate 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.
Related questions
The reactance of a capacitor $C$ at frequency $f$ in an a.c. circuit is:A bird perched on a single high voltage wire is unharmed because:The two conservation laws embodied in Kirchhoff's rules are conservation of:The resistance offered by the cell itself is called:Which device detects the current in a Wheatstone bridge?In a Wheatstone bridge, the source is connected across the:The Wheatstone bridge is made up of how many resistors?At a junction, the current entering equals the current: