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. A) 16 mm B) 16 cm C) 1.6 m D) 16 m E) 160 m

Question

Quizplus · Accepted Answer

The resistance R of a wire is given by R = ρL/A, where ρ is resistivity, L is length, and A is cross-sectional area. The area A = π(d/2)^2. Solving for L gives L = RA/ρ. Substituting the given values, L = (15 Ω)(π(0.15×10^-3 m/2)^2)/(1.68×10^-8 Ω•m) ≈ 16 m.

What Length of a Certain Metal Wire of Diameter 0