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Magnets
Electromagnets
Motors and Generators
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100
A __________ is any object with magnetic force.
What is a "magnet"
100
An ___________ is a coil of wire wrapped around a metal core, such as an iron bar.
What is an "electromagnet"
100
An electric ______ is a device that changes electrical energy into mechanical energy or motion.
What is a "motor"
100
Electrical energy is produced by a __________.
generator
200
The parts of a magnet where the magnetic force is strongest are called the magnetic ______.
What are "poles"
200
A _________ is a device that changes electrical energy into sound.
What is a "loudspeaker"
200
An electric _______ turns motion into electrical energy.
What is a "generator"
200
Every magnet has a north and a south ______.
What are "poles"
300
A _________ is the area of magnetic force around a magnet.
What is a "magnetic field"
300
A ________ is a device that uses a magnet to convert sound into electrical signals.
What is a "microphone"
300
___________ flows in one direction and then flows in one direction and then flows in the opposite direction.
What is "alternating current"
300
The area of magnetic force around a magnet is called its _____.
What is a "magnetic field"
400
Why is a compass a useful instrument for hikers?
A compass needle points north and can help hikers find their way.
400
What devices use electromagnets?
microphones, loudspeakers, stereos, televisions, telephones
400
When the flow of a current is always in one direction, it is called a _________.
What is "direct current"
400
Earth's magnetic field causes a _________ to point north.
What is a "compass"
500
What changes happen within a metal object when it becomes magnetic?
The tiny magnetic particles within the object spin around and line up.
500
How is an electromagnet different from a permanent magnet?
Electromagnets can be turned off and on. They can also have the strength of the magnet increase and decrease.
500
What is one way that electricity can be generated?
Electrical energy can be generated by spinning a magnet inside a loop of wire.
500
Electric current produces a magnetic field in an ________.
What is an "electromagnet"