Chapter 18 Study Guide
If a loop of wire moves in and out of a magnetic field, a _____ is induced.
current
What is the magnetic field produced by a solenoid similar to?
A bar magnet.
What shape does a magnetic field around a current-carrying wire form?
A closed loop.
Where do magnetic fields exist?
Around any magnetized material.
How can the strength of the magnetic field of a solenoid be increased?
By increasing the number of coils.
What shape do magnetic field lines always form?
Closed loops
What is a magnet on a pivot that can rotate freely called?
Compass
What is a solenoid with a soft iron core called?
Electromagnet
Earth's magnetic field lines run in which direction?
From geographic south to geographic north.
Describe magnetic force: what type of force is it, where is it strongest, does it act at a distance?
It is a field force and it is strongest at the north and south poles. It does act at a distance, but it is weaker the farther away from the poles.
In which direction will the needle of a compass placed near a current-carrying wire point?
It points in a direction tangent to a circle centered at the wire.
In which direction does a compass needle naturally point toward?
It points towards the south magnetic pole (north geographic pole).
What is the name for a region where a magnetic force can be detected?
Magnetic field
Where are Earth's magnetic poles are located?
North magnetic pole- Antarctica South magnetic pole- Northern Canada
How will the north pole of one magnet react to the north pole and south pole of another magnet?
North-North - Repel North-South- Attract
What method can you use to determine the direction of the magnetic field produced by a current-carrying wire?
Right-hand rule
____ poles of a magnet repel, while _____ poles attract one another.
Similar, opposite
What is a device that produces a magnetic field by wrapping wire into a coil?
Solenoid
How does the strength of the magnetic field of a magnet change with the distance from the magnet?
The closer the magnet is to an object, the stronger the magnetic field.
Compare and contrast Earth's magnetic poles with its geographic poles.
The geographic poles indicate where the northern and southern hemispheres are located. The magnetic poles indicate where the magnetic field lines run.
What is magnetism caused by?
The movement of charges.
Where are Earth's magnetic poles are located?
The south magnetic pole is in northern Canada. The magnetic north pole is in Antarctica.
What will the north pole of one magnet be attracted to on another magnet?
The south pole of the magnet.
Do magnetically soft substances retain or lose their magnetism easily? Are they magnetized easily or not?
They lose their magnetism easily and are magnetized easily.
How do like magnetic poles react to each other?
They repel each other.
A galvanometer uses an electromagnet to detect and measure the _____ in a circuit.
current
The _____ North and South poles are not aligned exactly with the magnetic north and south poles of Earth.
geographic
A magnetic force is the force due to the interaction of __________________.
magnetic fields
The magnetic field of a magnet is strongest _____ the magnet.
nearest
The north poles of two different magnets will _____ one another.
repel
Increasing the number of coils in a solenoid or an electromagnet results in a _____ magnetic field.
stronger
The magnetic field of a solenoid is generally _____ that of an electromagnet.
weaker than
What is a device that converts electrical energy into mechanical energy?
A generator.
Which type of magnet can be easily magnetized and demagnetized?
A soft magnet.
What does an electric motor convert electrical energy into?
Mechanical energy
Describe how to apply the right-hand rule, and explain how it determines the direction of the magnetic field produced by a current.
You grab a wire in your hand with your thumb pointing in the direction of the current. The direction your fingers are curling is the same direction the magnetic field is going.