The diameter of a copper wire that is being used in a high voltage power line is 8.252 mm. What is the resistance in Ohms of a power line that is 361 miles long if it is 20oC

182.45Ω

Explanation:

Hi to answer this question we have to apply the next formula:

Resistance = ρL /A

Where:

ρ = resistivity of copper at 20° ( 1.68 x 10^-8 Ωm)

L = lenght

A = transversal area = π (diameter /2)^2 = π (8.252x10^-03 /2)^2 =

5.35 x10^-05

Since

1 mile = 1,609 meters

361 miles = 580,849 meters  (length)

1 mm = 0.001 meter

8.252 mm = 8.252x10^-03 m  (diameter)

Resistance = [ 1.68 x 10^-8 (580,849)]/(5.35 x10^-05) = 182.45Ω

Feel free to ask for more if needed or if you did not understand something.