A 5000-km long cable consists of seven copper wires, each of diameter 0.85 mm, bundled together and surrounded by an insulating sheath. Calculate the resistance of the cable. Use 3x10^-6 cm.Ω for the resistivity of the copper.

The resistance of the cable is 37762.91 ohms.

Explanation:

let L be the length of the cable, A be the cross-sectional area of the cable and r be the resistivity of the copper.

then, the resistance of the cable is given by:

R = r*L/A

= (3*10^-8) * (5000*10^3) / (7*π ((0.85*10^-3) / 2) ^2)

= 37762.91 ohms

Therefore, the resistance of the cable is 37762.91 ohms.