Modified True/False
Indicate
whether the statement is true or false. If false, change the identified word or phrase to make the
statement true.
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1.
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The magnetic domain is the area around a magnet where the force acts.
_________________________
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2.
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When you bring the south ends of two magnets close together, they repel
each other. _________________________
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3.
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A paper clip magnetized by a bar magnet is permanently magnetized.
_________________________
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4.
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The field of a magnet is weakest at its poles.
_________________________
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5.
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The magnetic domains of a permanent magnet are arranged randomly.
_________________________
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6.
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The south pole of a compass points to the geographic north pole.
_________________________
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7.
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A current-carrying wire produces a magnetic field.
_________________________
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8.
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The strength of an electromagnet can be increased by reducing the number
of turns on the wire coil so that more current can flow. _________________________
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9.
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An electric motor is used to change mechanical energy into electrical
energy. _________________________
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10.
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In an electric motor, a magnetic field causes a current-carrying loop to
spin. _________________________
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11.
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The Earth's magnetic field is called the magnetic domain.
_________________________
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12.
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Because of the magnetic field, magnets do have to touch to affect each
other. _________________________
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13.
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Moving a wire through a magnetic field creates an electric current in the
wire. _________________________
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14.
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Before alternating current from a power plant can enter a home, its voltage must
be increased. _________________________
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15.
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The input current to a transformer is direct current.
_________________________
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Multiple Choice
Identify the
choice that best completes the statement or answers the question.
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16.
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The south pole of a magnet ____.
a. | attracts another south pole | c. | attracts a north
pole | b. | repels a paper clip | d. | repels a north pole |
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17.
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When you break an iron magnet into two pieces, you get ____.
a. | two north poles | b. | two south poles | c. | two north poles and
two south poles | d. | a piece of iron that is no longer magnetic |
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18.
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The location of the strongest magnetic field is the ____.
a. | center of the magnet | c. | magnetic fields | b. | magnetic domains | d. | magnetic poles |
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19.
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The region around a magnet where the magnetic forces act is the ____.
a. | electromagnetic pole | c. | magnetic field | b. | magnetic domain | d. | magnetic pole |
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20.
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The magnetic field of a magnet is ____.
a. | the same at all parts of the magnet | c. | strongest at the
poles | b. | strongest at the center | d. | weakest at the poles |
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21.
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Atoms become magnets when their ____ are properly arranged.
a. | electrons | c. | neutrons | b. | protons | d. | positrons |
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22.
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The atoms in a magnet are ____.
a. | arranged randomly | c. | negatively charged | b. | lined up | d. | positively
charged |
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23.
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The aurora borealis is seen mainly ____.
a. | at the equator | c. | over oceans | b. | near the poles | d. | on high
mountains |
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24.
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Particles in the solar wind react with ____ in the atmosphere to produce the
aurora.
a. | clouds | c. | pollution | b. | water vapor | d. | atoms |
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25.
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An electromagnet is ____.
a. | a permanent magnet | b. | made with bar magnets | c. | attracts all metal
substances | d. | only operating when the current is on |
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26.
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The function of an electric motor is to change ____.
a. | chemical energy into electrical energy | b. | electrical energy into chemical
energy | c. | electrical energy into mechanical energy | d. | mechanical energy
into electrical energy |
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27.
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A current carrying wire wrapped around an iron ore is called a(n) ____.
a. | generator | c. | transformer | b. | conductor | d. | electromagnet |
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28.
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Changing the current changes the ____ of an electromagnet.
a. | strength | c. | charge | b. | direction | d. | strength and
direction |
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29.
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The function of a generator is to change ____.
a. | chemical energy into electrical energy | b. | electrical energy into chemical
energy | c. | electrical energy into mechanical energy | d. | mechanical energy
into electrical energy |
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30.
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A device that increases or decreases voltage in a power line is a ____.
a. | commutator | c. | motor | b. | generator | d. | transformer |
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31.
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Current that does not reverse direction is called ____.
a. | alternating current | c. | direct current | b. | circuit current | d. | magnetic
current |
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32.
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A current that reverses direction in a regular pattern is called a(n)
____.
a. | circuit current | c. | direct current | b. | alternating current | d. | magnetic
current |
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33.
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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.
a. | input, output, input, output | c. | output, input, input,
output | b. | input, output, output, input | d. | output, input, output,
input |
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Completion
Complete each
statement.
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34.
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A compass needle acts as a(n) ____________________.
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35.
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Unlike poles of a magnet ____________________.
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36.
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The domains in an unmagnetized paper clip are ____________________
arranged.
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37.
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A group of atoms with their magnetic poles aligned make up a(n)
______________________________.
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38.
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______________________________ is Earth's magnetic field extended into
space.
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39.
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A doorbell uses a(n) ____________________ to operate.
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40.
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A(n) ______________________________ will push on a current-carrying wire.
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41.
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An electric motor converts electrical energy into ____________________.
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42.
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Homing pigeons have pieces of ____________________ in their brains to help them
find their way home.
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43.
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Alternating current is current that ____________________ direction.
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