BJU Physical Science Chapter 20 (6th edition)

north pole of a magnet

the pole from which the magnetic field lines EXIT from a magnet

south pole of a magnet

the pole into which the magnetic field lines ENTER a magnet

what kind of force (repulsive or attractive) is represented in the diagram?

repulsive

Where does Earth's magnetic field originate?

deep inside the earth

a group of atoms whose magnetic fields are aligned

magnetic domain

a strong magnet's domains will...

be aligned in the same direction

What will most likely happen to the magnetic field of a magnet heated over a flame?

weaken its magnetic field

If all other factors are the same, what would produce the greatest magnetic field when electrified?

an electromagnet

Name two scenarios that result in electromagnetic induction.

1) a bar magnet is moved through a coil

2) a coil of wire is moved in a magnetic field

How do electrical generators produce AC power?

by rotating wire coils within stationary magnetic fields OR by rotating magnetic fields within stationary wire coils

the main difference between AC and DC generators is what?

the DC generator contains a commutator

commutator

A device that controls the direction of the flow of current through an electric motor

For a transformer to produce the highest output voltage, how would it need to be set up?

a higher number of wraps in the output coil than in the input coil

Was magnetism a recent discovery?

no. the Greeks knew about magnetism through magnetic rocks

What will a magnetic north pole attract?

a magnetic south pole

Do opposites attract or repel?

attract

what type of force is magnetism?

field force

What is an interesting fact about the earth's magnetic South Pole?

it is actually a north magnetic pole

Which of the earth's poles are fixed? Which of the earth's poles are changing?

geographic poles are fixed. Magnetic poles are constantly changing location.

What type of materials can become weakly magnetic in the presence of a magnetic field?

non-ferromagnetic materials

When a strong magnet is near non-ferromagnetic material, what can happen?

the creation of temporary magnets

What does flowing current in a wire always produce?

a magnetic field

a magnetic field around a wire can produce a current in the wire ONLY IF...

the magnet is moving

electrical generators convert _______________________ energy into _________________________ energy.

mechanical energy into electrical energy

Motors convert ___________ energy into ________________________________ energy.

electrical energy into rotary mechanical energy

What do electric motors use to cause interaction between the magnetic fields of the magnet and the wire coil's current?

electricity

What type of generator includes a commutator that allows current to flow in only one direction?

DC generator

Can a solenoid induce an electric current in a nearby, unconnected solenoid?

yes.

what types of transformers do electric companies use?

both step-up transformers and step-down transformers

What can induce an electric current in a wire?

a moving magnet AND moving a wire through a magnetic field

a coil of wire that can act as a magnet

solenoid

a group of atoms whose magnetic fields are aligned

magnetic domain

that which limits current flow to only one direction

commutator

an area of concentrated magnetic force

magnetic pole

an electrified wire coil paired with a strong magnet inside

electromagnet

identified by the ancient Greeks as being able to attract metal objects

lodestone

that which increases or decreases the voltage of an AC current

transformer

that which produces electric current using wire coils and a magnetic field

generator

the region surrounding the magnet where it can exert a magnetic force

magnetic field

who observed that an electric current caused a compass needle to move?

Oersted

who observed that magnetic properties are concentrated at two locations?

de Maricourt

who observed that placing a ferromagnetic bar inside a solenoid greatly increased the force of the magnetic field

Sturgeon

Who observed that two parallel wires carrying current in the same direction are magnetically attracted?

Ampere

Who published DeMagnete, the first comprehensive book on the properties of magnets?

Gilbert