A straight overhead power-line conductor runs exactly east–west for a distance of 400 m between two towers. It carries a steady current of 150 A from west to east. The horizontal component of the Earth’s magnetic field at the location is 4.0×10−5T directed from geographic north to south, making the conductor effectively perpendicular to the field.
Read the data carefully and answer the following questions. Take g=10ms−2.
a. (i) Calculate the magnetic force acting on the 400 m length of the conductor due to the Earth’s magnetic field.
b. (ii) The conductor has a mass per unit length of 1.2 kg m−1. Find the weight of the 400 m segment and compare its magnitude with the magnetic force obtained in part (i).
c. (iii) State ONE reason why, in spite of your comparison in part (ii), power-lines can still sway when large currents flow through them.