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A potential difference of 5 V is maintained across a wire of length 0.1 m, producing a drift speed of 2.5 * 10⁻⁴ m/s for the conduction electrons. Given the free-electron density is 8 * 10²⁸ m⁻³, the resistivity of the wire material is approximately:

1. 1.6 * 10⁻⁶ Ohm m
2. 1.6 * 10⁻⁵ Ohm m
3. 1.6 * 10⁻⁸ Ohm m
4. 1.6 * 10⁻⁷ Ohm m

Correct answer: 1.6 * 10⁻⁵ Ohm m

Solution

Using E = V/L and j = n*e*v_d, resistivity rho = E/j gives about 1.6 * 10⁻⁵ Ohm m.

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