Question

High-voltage power lines are a familiar sight throughout the country. The aluminum (resistivity = 2.82 x 10-8Ω m) wire used for some of these lines has a cross-sectional area of 5.9 x 10-4 m2. What is the resistance of 14 kilometers of this wire?

Answer 1

The total resistance of a section of wire can be calculated using the equation pL/a, where “p” represents the resistivity of the material, “L” represents the length, and “a” represents the cross-sectional area. For this problem, simply substitute and simplify

Rwire = pL/a

= (2.82x10^-8)(14,000 m)/(5.9x10^-4)

= 0.6692 ohms

The resistance of this wire under these conditions would be approximately 0.67 ohms.

Hope this helps!