(a) Explain the factors which govern the variation of resistance of conductors. (6)

(b) A 2-core cable, each core of which is 300 m long and of uniform cross-sectional area of 150 mm2 is fed from one end at 240V. A load of 200A is taken off from the centre of the cable and a load of 100A from the far end. Calculate the voltage at each load. A single-core cable of similar material 880 m in length and of uniform cross-sectional area of 50mm2 has a resistance of 0.219Ω. (10)