Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
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1.
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Which
of the following situations is not true for magnets? a. | Like poles repel
each other. | b. | Unlike poles repel each other. | c. | North poles
repel each other. | d. | A north pole and a south pole will attract each
other. | | |
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2.
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Where
is the magnitude of the magnetic field around a permanent magnet greatest? a. | The magnitude is
greatest close to the poles. | b. | The magnitude is greatest far from the
poles. | c. | The magnitude is equal at all points on the
field. | d. | The magnitude is greatest halfway between
poles. | | |
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3.
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Which
compass needle orientation in the figure above might correctly describe the magnet’s field at
that point?
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4.
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A
microscopic magnetic region composed of a group of atoms whose magnetic fields are aligned in a
common direction is called a(n) ____. In most materials, when these groups are randomly distributed,
the substance will show ____ no magnetism. a. | domain; no | c. | cell; unusual | b. | pole;
some | d. | ion;
strong | | | | |
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5.
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In a
permanent magnet, a. | domain alignment
persists after the external magnetic field is removed. | b. | domain alignment
becomes random after the external magnetic field is removed. | c. | domains are
always randomly oriented. | d. | the magnetic fields of the domains cancel each
other. | | |
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6.
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Which
statement describes Earth’s magnetic declination? a. | the angle
between Earth’s magnetic field and Earth’s surface | b. | Earth’s
magnetic field strength at the equator | c. | the tendency for Earth’s field to reverse
itself | d. | the angle between true north and north indicated by a
compass | | |
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7.
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A
current in a long, straight wire produces a magnetic field. These magnetic field
lines a. | radiate out from
the wire to infinity. | b. | come in from infinity to the wire. | c. | form circles
that pass through the wire. | d. | form circles that go around the wire. | | |
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8.
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When
an iron rod is inserted into a solenoid coil’s center, the magnetic field produced by the
current in the loops a. | causes the iron to return to an unmagnetized
state. | b. | forces the domain in the iron out of
alignment. | c. | causes random orientation of the domains in the
iron. | d. | causes alignment of the domains in the
iron. | | |
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9.
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Which
of the following modifications to a solenoid would be most likely to decrease the strength of its
magnetic field? a. | removing its
iron rod core and increasing the number of coils | b. | increasing the
current and reducing the number of coils | c. | reducing the number of coils and inserting an iron
core | d. | decreasing the
current and reducing the number of coils | | |
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10.
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According to the right-hand rule, if a current-carrying wire is grasped in the right
hand with the thumb in the direction of the current, the four fingers will curl in the direction
of a. | the magnetic
force,  . | c. | the current’s velocity,  . | b. | the magnetic field,  . | d. | the current’s path,  . | | | | |
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11.
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The
lines of the magnetic field around a current-carrying wire a. | point away from
the wire. | b. | point toward the wire. | c. | form concentric
circles around the wire. | d. | are parallel with the wire. | | |
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12.
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An
electron moves north at a velocity of 4.5 ´ 10 m/s and has a magnetic
force of 7.2 ´ 10 N exerted on it. If the
magnetic field points upward, what is the magnitude of the magnetic field? a. | 1.0
mT | c. | 3.6
mT | b. | 2.0
mT | d. | 4.8
mT | | | | |
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13.
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An
electron that moves with a speed of  perpendicular to a uniform
magnetic field of 0.40 T experiences a force of what magnitude? ( = 1.60
´ 10 C)
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14.
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The
direction of the force on a current-carrying wire in an external magnetic field is a. | perpendicular to
the current only. | b. | perpendicular to the magnetic field
only. | c. | perpendicular to both the current and the magnetic
field. | d. | parallel to the current and to the magnetic
field. | | |
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15.
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A
stationary positive charge, Q, is located in a magnetic field, B, which is directed
toward the right. What is the direction of the magnetic force on Q? a. | toward the
right | c. | down | b. | up | d. | There is no magnetic force. | | | | |
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16.
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Consider two long, straight, parallel wires, each carrying a current I. If the
currents move in the same direction, a. | the two wires will attract each
other. | b. | the two wires will repel each other. | c. | the two wires
will exert a torque on each other. | d. | neither wire will exert a force on the
other. | | |
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17.
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A
current-carrying conductor in and perpendicular to a magnetic field experiences a force that
is a. | perpendicular to
the current. | b. | parallel to the current. | c. | inversely
proportional to the potential difference. | d. | inversely proportional to the
velocity. | | |
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18.
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A
proton move perpendicularly to a magnetic field that has a magnitude of 4.20 x 10-2 T/
What is the speed of the particle if the magnitude of the magnetic force on it is 2.40 x 10-14
N? a. | 3.57 x 106
m/s | c. | 8.75 x 1016
m/s | b. | 8.75 x 106 m/s | d. | 3.57 x 1016 m/s | | | | |
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19.
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A 6.0
m wire carries a current of 7.0 A toward the +x direction. A magnetic force of 7.0 x 10-6
N acts on the wire in the -y direction. Find the magnitude and direction of the magnetic field
producing the force. a. | 1.7 x 10-7 T in +z
direction | c. | 7.1 x
107 T in -z direction | b. | 7.1 x 10-7 T in -z
direction | d. | 1.7 x
107 T in +z direction | | | | |
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20.
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A
straight segment of wire has a length of 25 cm and carries a current of 5.0 A. If the wire is
perpendicular to a magnetic field of 0.60 T, than what is the magnetude of the magnetic force on this
segment of the wire? a. | 0.75 N | c. | 1.35 N | b. | 750
N | d. | 135
N | | | | |
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