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43 terms

Chapter 8 Test

STUDY
PLAY
A device that increases or decreases voltage in a power line is called a ____.
transformer
Current that does not reverse direction is called ____.
direct current
The location of the strongest magnetic forces on a magnet are the ____.
magnetic poles
Current that reverses direction in a regular pattern is called ____.
alternating current
The region around a magnet where the magnetic forces act is the ____.
magnetic field
Objects that keep their magnetic properties for a long time are called ____.
permanent magnets
An instrument that measures electric current is a ____
galvanometer
A reversing switch that rotates with the coil in an electric motor and reverses the direction of the current every half turn is a ____.
commutator
A device that increases or decreases the voltage of an alternating current is a ____.
transformer
In a step-up transformer, the number of turns of wire is greater in the ____ coil than in the ____ coil, and the ____ voltage exceeds the ____ voltage.
secondary, primary, output, input
The function of an electric motor is to ____.
change electrical energy to mechanical energy
The function of a generator is to ____.
change mechanical energy to electrical energy
A ____ attracts iron objects.
magnet
____ is the process of producing an electric current by moving a loop of wire through a magnetic field.
Electromagnetic induction
The atoms in a magnet are ____.
aligned according to their magnetic poles
A galvanometer measures ____.
electric current
A transformer that increases voltage is a ____.
step-up transformer
Alternating current is transmitted across large distances at high voltage to minimize ____.
energy loss as heat
Groups of atoms with aligned magnetic poles are called ____.
magnetic domains
The strength of magnetic force in an electromagnet is ____ by increasing the current through the coil.
increased
The south pole of a magnet will ____________________ the south pole of another magnet.
repel
A large wheel that rotates when pushed by water, wind, or steam. ____________________
turbine
The properties and interactions of magnets are referred to as ____________________.
magnetism
A(n) ____________________ is formed by placing a piece of iron inside a current-carrying coil of wire.
electromagnet
A machine that changes electrical energy to mechanical energy is a(n) ____________________ used to do work, such as turning a fan.
electric motor
A device that produces an electric current by rotating a coil of wire in a magnetic field is a(n) ____________________.
generator
The process by which moving a wire through a magnetic field produces an electric current is _________________________.
electromagnetic induction
Step-up Transformer
increase voltage
Step-down Transformer
decrease voltage
Which coil will be larger in a step up transformer?
Secondary coil
Which coil will be larger in a step down transformer?
Primary coil
What type of energy is needed for a motor to run?
Electrical Energy
What type of energy is produced by a motor?
Mechanical Energy
Which part inside a motor is the source of the movement?
Electromagnet
What happens to the rotation of the coil in a motor if the current flowing through it is increased?
it rotates faster with greater force
What mineral is a natural magnet?
magnetite
What happens to the direction of the magnetic field around a wire when the direction of the current is changed?
the magnetic field will reverse its direction
A wire wrapped into a cylindrical wire coil is called a(n) ___.
solenoid
List 3 metals that are magnetic.
iron, nickel, cobalt
Groups of atoms with aligned magnetic poles are called _____.
domains
What happens when a magnet is heated?
domains un-align
How can an iron nail be changed into a magnet?
put it inside a solenoid
How can the magnetic field of a solenoid be strengthened? 2 Ways
more coils, more current