Application: Resistance and power in faulty cables. An underwater cable is made as a coaxial cable with internal conductor of diameter a = 10 mm, external conductor diameter b = 20 mm (see Figure 7.40). The cable is made of a superconducting material ( σ = ∞), is 10 km long and operates at 480 V. Because of a leak, seawater ( σ = 4 S/m) entered the cable, filling the space between the conductors.
(a) What is the resistance seen by a generator connected to the cable at one end?
(b) How much power is dissipated in the seawater inside the cable?
