Magnetic Properties of A Solenoid

Shortly after Oersted discovered the magnetic effect of a current-carrying wire, Ampere found that a loop or coil of wire (a single loop or a coil of several turns of wire) acted as a magnet. A coil of wire of this kind is sometimes referred as a "solenoid," or as a "helix." The magnetic lines of force in a solenoid are such that one side or end of the coil acts like a "N" magnetic pole and the other side or end like a "S" magnetic pole. At all points in the region around a coil of wire carrying a current, the direction of the magnetic field, as shown by a compass, can be predicted by the left-hand rule. Inside each loop or turn of wire, the lines point in one direction, whereas outside they point oppositely. Outside the coil, the lines go the same way they do about a permanent bar magnet, whereas inside the coil they go from "S" to "N". Not only does one coil of wire act like a magnet, but two coils will demonstrate the repulsion and attraction of like and unlike poles.