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Date _____________
Chapter 21 Magnetism
Chapter Test B
Multiple Choice
Write the letter that best answers the question or completes the statement on
the line provided.
1. The force a magnet exerts on another magnet, on iron or a
similar metal, or on moving charges is
a. an electric force.
b. a magnetic force.
c. proportional to the charge of the magnet.
d. proportional to the mass of the magnet.
2. Which of the following statements describes the interaction
between magnetic poles?
a. Like poles attract each other.
b. Like poles repel each other, and opposite poles attract
each other.
c. Opposite poles repel each other.
d. Like poles attract each other, and opposite poles repel
each other.
3. How does the magnetic force exerted by a magnet change as
the distance between two magnets increases?
a. The magnetic force increases.
b. The magnetic force stays the same.
c. The magnetic force decreases.
d. The magnetic force does not change with distance.
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4. What is the name of the area surrounding Earth that is
influenced by Earth’s magnetic field?
a. magnetosphere
b. atmosphere
c. magnetic domain
d. magnetic declination
5. A region that has a large number of atoms whose magnetic
fields are lined up parallel to a magnet’s field is
a. the magnetosphere.
b. the magnetic declination.
c. a magnetic domain.
d. a ferromagnetic region.
6. A ferromagnetic material that has domains that remain
aligned for a long period of time is called
a. a neutral object.
b. nonmagnetic.
c. a permanent magnet. d. a temporary magnet.
7. What creates a magnetic field?
a. charged particles that do not move
b. moving electric charges
c. gravity
d. an isolated magnetic pole
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Chapter 21 Test B
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8. If a current-carrying wire is in a magnetic field, in what
direction will a force be exerted on the wire?
a. perpendicular to the magnetic field and parallel to the
current direction
b. parallel to both the current direction and the magnetic
field
c. perpendicular to the current direction and parallel to the
magnetic field
d. perpendicular to both the magnetic field and the current
direction
9. A coil of wire that is carrying a current and produces a
magnetic field is
a. a galvanometer.
b. a solenoid.
c. a magnetic domain.
d. an electric motor.
10. Which of the following is the reason “soft” iron is used for
the cores of electromagnets?
a. It is difficult to magnetize.
b. It is easily magnetized.
c. It has no magnetic domains.
d. It is a permanent magnet.
11. The device that measures current in a wire by using the
deflections of an electromagnet in an external magnetic
field is
a. a galvanometer.
b. a solenoid.
c. an electric motor.
d. a loudspeaker.
12. The process of generating an electric current by moving an
electrical conductor relative to a magnetic field is called
a. magnetization.
b. electromagnetic force.
c. electromagnetic induction.
d. alternating current.
14. The strength of the output voltage and current of a
transformer are determined by the
a. number of turns in the primary and secondary coils.
b. strength of the DC current in the primary coil.
c. ferromagnetic material of the rings connecting the coils.
d. direction of the current in the primary coil.
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Chapter 21 Test B
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13. A device that changes mechanical energy to electric
energy by rotating a coil of wire through a magnetic field
is called a(an)
a. transformer.
b. generator.
c. electromagnet.
d. current meter.
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15. Before electric current in power lines can be safe for your
home, it must pass through a
a. turbine.
b. step-down transformer.
c. step-up transformer
d. generator.
Completion
Complete each statement on the line provided.
1. The region around a magnet that exerts magnetic force is called
a(an)
.
2. In most materials, the magnetic fields of
cancel their effects.
3. The
are caused by charged particles from
the sun entering Earth’s magnetic field.
4. In ferromagnetic materials, regions with large numbers of atoms
with aligned magnetic fields are called
.
5. A charged particle moving in a magnetic field will be deflected in
a direction
to the magnetic field.
6. In a solenoid, there will be no magnetic field if there is no
in the wires of the coil.
7. Moving a magnet through a wire coil can produce a(an)
in the coil.
8. A(An)
converts mechanical energy into
electric energy.
9. Large power plants in the United States currently use
generators.
10.
transformers decrease the current and
increase the voltage in the output circuit.
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Short Answer
In complete sentences, write the answers to the questions on
the lines provided.
1. What are magnetic poles?
2. In Figure 21-1, what do the lines around the bar magnets
represent?
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Chapter 21 Test B
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Date _____________
3. What is a generator and how does it work?
4. List five energy sources that are used in the United States to
produce electrical energy.
5. How is water used to produce electric energy in a hydroelectric
power plant?
Using Science Skills
Use the diagram to answer each question. Write the answers on a separate
sheet of paper.
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Chapter 21 Test B
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North
1. Interpreting Graphics In
geographic pole
N
Figure 21-1, use the
direction of the magnetic
W
E
Magnetic pole
field lines to determine
S
what type of magnetic
Magnetic
pole is located at the
field
magnetic South Pole.
2. Predicting Use Figure 21-1
to predict where Earth’s
magnetic field is strongest.
Explain your answer.
3. Inferring Use Figure 21-1
Magnetic pole
to determine in what
South
direction the north
geographic pole
magnetic pole of the
Figure 21-1
compass will point.
What type of magnetic pole is the compass pointing toward?
4. Applying Skills A scientist studying Earth’s magnetic field found
that at Hot Springs, Arkansas, her compass pointed 5° east of true
north. In Durango, Colorado, she took another reading and found
that her compass pointed 14° east of true north. Use Figure 21-1 to
explain why the two readings were different.
5. Interpreting Graphics In Figure 21-1, where is the magnetic field
the weakest?