MAGNETISM NOTES

MAGNETS Magnetic domain – region of a magnetic

material where the atoms are groups together and aligned Has uniform magnetization

MAGNETS Poles of a magnet are the ends where objects

are most strongly attracted 2 poles called North and South

Like poles repel Opposite poles attract If a magnet is broken into 2 pieces, each

piece will still have an N and S

MAGNETS Iron is the most common magnetic material Unmagnetized iron can be magnetized via

conduction (stroking) or induction

MAGNETIC FIELD The region of space surrounding a moving

charge Is a vector quantity (arrows)

MAGNETIC FIELD

Attraction

Repulsion

ELECTROMAGNET Electric current produces a magnetic field Made from current flowing through coils of

wire (called a solenoid) Faraday’s Law: More coils = stronger

electromagnet (more voltage)

ELECTROMAGNET

ELECTROMAGNET

RIGHT-HAND THUMB RULE

MOTORS AND GENERATORS

PBS AC Generator AnimationMotors and Generators Video

TRANSFORMERS

JUST KIDDING!

BUT SERIOUSLY….

ELECTRICAL TRANSFORMERS Device that transfers energy and changes

the amount of voltage Has 2 winding circuits and current varies

between them causing magnetic flux (a measure of the amount of magnetic field passing through a given surface)

ELECTRICAL TRANSFORMERS Step-Up Transformer

Increases voltage Step-Down Transformer

Decreases voltage

ELECTRICAL TRANSFORMERS NOT 100% efficient!!!

Not all of the input electrical energy is transferred to electrical energy at the output.

There is some heat generated and also a little bit of sound - transformers get hot and hum!