Resistivity: What length of a certain metal wire of diameter 0.15 mm is needed for the wire to have a resistance of 15 Ω? The resistivity of this metal is 1.68 × 10^-8 Ω ∙ m.

Question

Quizplus · Accepted Answer

To find the length of the wire, use the formula for resistance: R = ρ(L/A), where R is resistance, ρ is resistivity, L is length, and A is the cross-sectional area. First, calculate the area A = π(d/2)^2 = π(0.15 × 10^-3 / 2)^2. Then, solve for L: L = R * A / ρ = 15 * π(0.15 × 10^-3 / 2)^2 / 1.68 × 10^-8, which gives approximately 16 m.

Resistivity: What Length of a Certain Metal Wire of Diameter