Magnetism
Magnetism 2
Electricity and Magnetism
Producing Electric Current
Overview
100
What was the mineral called before the Greeks called it "Magnetic?"
Magnesia.
100
A magnetic ______ exerts a force on other magnets and objects made of magnetic materials.
Field
100
A(n) __________ is a temporary magnet made by wrapping a wire coil carrying a current around an iron core.
Electromagnet
100
The generation of a current by a changing magnetic field is called a(n) what?
Electromagnetic Induction.
100
An alternating current changes direction in a ______ pattern.
Regular
200
The strength of the force between two magnets ______ as magnets move closer together decreases as the magnets move ______ apart.
increases; farther.
200
Why does the needle of a compass always point North?
Because, Earth acts like a giant bar magnet and is surrounded by a magnetic field that extends into space.
200
What kind of energy is converted from the electromagnet to produce sound?
Electrical energy into Mechanical energy.
200
Most of the electrical energy you use every day is provided by ______.
Generators
200
Define transformer
a transformer is a device that increases or decreases the voltage of an alternating current.
300
What occurs when opposite poles of magnets come together?
They attract.
300
How can the magnetic field be represented?
By lines of force, or magnetic field lines.
300
What is a solenoid?
A single wire wrapped into cylindrical wire coil.
300
What does a generator use electromagnetic induction for?
To transform mechanical energy into electrical energy.
300
What is a step-up transformer?
Increases the voltage so that the output voltage is greater than the input voltage.
400
What are Magnetic Domains?
Groups of atoms with aligned magnetic poles.
400
In a permanent magnet, a strong magnetic field _____ domains and they remain aligned when the field is ______.
aligns; removed.
400
A galvanometer uses an electromagnet to do what?
Measure electric current.
400
Give the example of a generator and explain. (Turbine)
A turbine - a large wheel that rotates when pushed by water, wind, or steam.
400
A step-down voltage is ?
a transformer that decreases the voltage so that the output voltage is less than the input voltage.
500
What two poles are on a magnet?
North and South Pole.
500
Name 3 Elements that have atoms that behave like magnets.
Iron, Cobalt, and Nickel.
500
A magnetic field surrounds a moving ______ charge. A) Mechanical B) Electric C) Permanent
B) Electric
500
A direct current flows in how many directions?
Only one.
500
power plants commonly produce alternating current because the voltage can be increased or decreased with __________?
(transformers)
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