MAGNETS AND MAGNETIC FIELDSCh 21.1

True False Statement True False

South poles attract North poles, and the same poles repel

The Earth is a giant magnet surrounded by a magnetic field

called the magnetosphere

A ferromagnetic material is always magnetic

Nonmagnetized materials have domains that are neatly arranged

Magnetized materials have domains that are randomly

arranged

MAGNETIC FORCES The force a magnet exerts on

Another magnet Iron or similar metal Moving charges

Magnetic Fields Region where force is strongest North and South

MAGNETIC FIELDS Surrounds a magnet and exerts a magnetic

force

Strongest near the poles Attracts or repels other magnets

MAGNETIC FIELDS

Earth is giant magnet Magnetosphere

Around Magnets Around Earth

MAGNETIC MATERIALS Magnetic Domains

Large # of atoms Aligned magnetic fields

Ferromagnetic Materials Can be magnetized due to domains

MAGNETIC MATERIALS

Domains arranged randomly

Domains arranged in an order

Nonmagnetized Magnetized

ELECTROMAGNETISM Ch. 21.2

True False Statement True False

Moving electric charges creates a magnetic field

Solenoids produce magnetic fields by vibrating in place

Electromagnets are solenoids with ferromagnetic cores

Electric motors use magnets to turn an axle

Electromagnetic forces are caused by electric charges

ELECTRICITY AND MAGNETISM Electromagnetic Force

Electric force = charged particles Magnetic force = movement of electrons

ELECTRICITY AND MAGNETISM

Moving electric fields create a magnetic fields

Charge will be deflected in a direction perpendicular to the magnetic field and velocity of charge

MF Around Moving Charges

Forces Acting on Moving Charges

SOLENOIDS AND ELECTROMAGNETS Solenoid

Coil of current carrying wire that produces a magnetic field

Electromagnet Solenoid with a

ferromagnetic core

Changing the current in an electromagnet controls the strength and direction of its magnetic field

ELECTROMAGNETIC DEVICES Change electrical

energy into mechanical energy

1. Galvanometer Uses solenoid

2. Electric Motors Uses electromagnets

3. Loudspeakers Uses solenoid

ELECTRICAL ENERGY GENERATION AND TRANSMISSIONCh 21.3

True False Statement True False

Electromagnetic induction is the process of generating voltage by moving an electrical conductor

relative to a magnetic fieldThere are AC and DC generators

that convert electrical energy into mechanical

Transformers increase or decrease voltage and current of linked AC

circuits

Turbines have blades that turn when pushed, helping generate

electricity

Faraday said current is induced in a conductor by changing the

magnetic field

GENERATING ELECTRIC CURRENT Electromagnetic Induction

Generating current by moving an electrical conductor relative to a magnetic field

Discovered by Faraday Voltage is induced in a conductor by a changing

magnetic field

GENERATOR Device converts mechanical energy into

electrical by rotating a coil of wire in a magnetic field

GENERATORS

Produces alternating current

Produces direct current

AC DC

TRANSFORMERS Device that increases or decreases voltage

and current of 2 linked AC circuits

Changes the magnetic field in 1 coil then induces an AC current in a nearby coil with a different # of turns

TRANSFORMERS

Decreases voltage and current

Increases voltage Decreases current

Step Down Step Up

ENERGY IN YOUR HOME Generated by coal,

water, nuclear, wind natural gas, and petroleum

Turbines Fanlike blades that

turn when pushed