Electromagnetism It’s attractive! (or repulsive)

Electromagnetism rules Magnetic fields exist in the region near a conductor when the circuit is closed. The direction of the field is dependent on the direction of the current in the conductor.

The intensity or strength of an electric or magnetic field can be determined by the lines representing it. The field intensity is proportional to the number of lines of force per unit area normal to the field. High intensity is represented by lines drawn close together, low intensity is represented by lines more widely separated.

Ampere’s Rule for a Straight Conductor: Grasp the conductor in the right hand with the thumb extended in the direction of the positive current. The fingers then will circle the conductor in the direction of the magnetic flux.

Ampere’s Rule for a Solenoid: Grasp the coil in the right hand with the fingers circling the coil in the direction of the positive current. The extended thumb will point in the direction of the North pole of the core.

Electromagnetic Induction An electric generator converts mechanical energy to electrical energy. An electric motor converts electrical energy to mechanical energy.

Generator Rule Right Hand Extend thumb, forefinger, and the middle finger of the right hand at right angles to each other. Let the forefinger point in the direction of the B flux from North to South and the thumb in the direction the conductor is moving. The middle finger points in the direction of the induced positive current.

Motor Rule Left Hand Extend the thumb, forefinger, and middle finger of the left hand at right angles to each other. Let the forefinger point in the direction of the B flux and the middle finger in the direction of the positive current. The thumb points in the direction of the motion of the conductor.