Glencoe Science Level Blue

Chapter 23: Magnetism

Magnetism

1
The input coil of a step-up transformer has 10 turns and its output coil has 100 turns. What is the voltage in the output coil if the input voltage is 50 V?
A)500 V
B)5500 V
C)4500 V
D)160 V
2
Electric current passing through a wire produces __________.
A)a permanent magnet
B)a magnetic field around the wire
C)a compass
D)geographic poles
3
Which of the following devices can increase or decrease the voltage of an alternating current?
A)transformer
B)battery
C)motor
D)generator
4
Alternating current changes the __________ of the current flow.
A)direction
B)amount
C)strength
D)voltage
5
North poles of magnets always attract __________.
A)negative charges
B)positive charges
C)other north poles
D)south poles
6
How do homing pigeons use Earth's magnetic field to find their way?
A)They have natural magnets on their feet.
B)They utilize GPS technology.
C)They pick up bits of magnetic material on their wings.
D)They have natural magnets in their brains.
7
What is the most common type of power plant?
A)coal burning
B)nuclear
C)wind power
D)hydroelectric
8
The __________ are regions where the magnetic force exerted by a magnet is strongest.
A)anodes
B)magnetic poles
C)magnetic field lines
D)cathodes
9
Which of the following changes electrical energy into kinetic energy?
A)transformer
B)electric motor
C)generator
D)superconductor
10
Magnetic field lines that curve away from each other show __________.
A)where the magnetic field is strongest
B)a magnetic domain
C)repulsion
D)attraction
11
The magnetic field that surrounds Earth is called the __________ .
A)magnetosphere
B)magnetron
C)magnetic domain
D)magnetic polar region
12
__________ flows in only one direction through a wire.
A)Alternating current
B)Direct current
C)Voltage
D)Electric current
13
Magnetic fields that surround all magnets exert __________.
A)the magnetic force
B)resistance
C)air pressure
D)electric current
14
What effect does increasing the current flowing in the wire have on an electromagnet?
A)It increases the strength of the magnetic field.
B)It causes it to become a permanent magnet.
C)It has no effect on the electromagnet.
D)It decreases the strength of the magnetic field.
15
Which of the following devices produces electric current?
A)compass
B)electric fan
C)generator
D)motor
16
Electric current should pass through a __________ after being transmitted by a power plant and before it enters your home.
A)turbine
B)step-down transformer
C)step-up transformer
D)generator
17
Magnetic fields are created by __________.
A)magnetic field lines
B)potential energy of molecules
C)spinning neutrons
D)moving electric charges
18
Iron is a magnetic material, but an iron nail does not behave like a magnet because __________.
A)its magnetic domains are aligned
B)it contains too few magnetic domains
C)the atoms in the iron exert a force on all the other atoms
D)its magnetic domains are arranged randomly
19
The negatively charged particles in an atom are called __________.
A)protons
B)negatrons
C)electrons
D)neutrons
20
Which of the following statements about Earth's magnetic field is true?
A)When molten rock cools, the iron in it no longer contains magnetic domains.
B)Earth's magnetic field extends about 10 m above Earth's surface.
C)It is possible for Earth's magnetic field to reverse.
D)A magnetic pole is permanent but a geographic pole is not.
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