A coaxial cable consists of an outer conductor and an inner conductor separated by an insulating plastic filler. These two conductors usually carry equal currents in opposite directions. You may have seen this type of configuration on cable TV hookups as well as on certain types of computer networks. The above simulation shows the progression of the magnetic field as many small wires are added to produce a coaxial configuration.
Watch the magnetic field change as the simulation first builds the outer conductor and then follows with the inner conductor. Explain why this type of cable might be preferable to household wiring which consists of two side-by-side wires carrying currents in opposite directions.
Click drag to measure the field at any point. Find the current passing through the inner conductor of the coaxial cable.