Effect of Iron Core in a Coil

Effect of Iron Core in a Coil Points : Effect of Iron Core in a Coil A coil of wire wound on a long straight core is called a solenoid. If a current is passed through a solenoid, it produces a magnetic field. The lines of force run approximately parallel to the axis of the solenoid until they reach the ends where they begin to diverge.
In fact, if the conductor is looped several times to form a helix (solenoid), a portion of flux produced by each turn will add up with a portion of flux produced by the other turns and link with the entire solenoid. No doubt, a portion of the flux will link with each turn separately, but this portion of the flux with each turn can be separately decreased by winding the turns of the solenoid closer together or also by placing magnetic material in the core of the solenoid.