A tiptop revision of magntism in physics ....

Fields, Currents and Forces.

When a current passes through a conductor, a magnetic field is produced. When a current is passed through a conductor in a magnetic field a force is produced.

Fleming’s left hand rule

This is used to find the direction of force, when the direction of the current and the magnetic directions are given.

IMPORTANT POINTS TO NOTE:

1.      The direction of the field is from north to south.

2.      The direction of current is from (+) pole.

3.      The rule can only be applied if the current and the field are at right angles.

·         THUMB=> Thrust (force)

·         FIRST=>      Field

·         SECOND=>Current

Increasing the force

1.      Increase the strength of the magnet.

2.      Increase the size of the magnet.

3.      Increase the length of the conductor.

(THIS FORCE IS USED IN THE “MOVING COIL LOUD SPEAKER” TO PRODUCE SOUND.)

Forces between current carrying conductors

If the currents flow in opposite direction they repel each other.