Name: ________________________ Class: ___________________ Date: __________
ID: A
Magnetism
22.1 Conceptual Questions
____
1) A proton, moving north, enters a magnetic field. Because of this field, the proton curves downward.
We may conclude that the magnetic field must have a component
A) downward.
B) upward.
C) towards the east.
D) towards the west.
E) towards the north.
____
2) A proton, moving west, enters a magnetic field. Because of this magnetic field the proton curves
upward. We may conclude that the magnetic field must have a component
A) towards the west.
B) towards the east.
C) towards the south.
D) towards the north.
E) downward.
____
3) An electron is moving to the right, as shown in the figure. Suddenly it encounters uniform magnetic
field pointing out of the page. Which one of the three paths shown will it follow in the field?
A) path a
B) path b
C) path c
____
4) Three particles travel through a region of space where the magnetic field is out of the page, as shown
in the figure. What are the signs of the charges of these three particles?
A)
B)
C)
D)
E)
1 is neutral, 2 is negative, and 3 is positive.
1 is neutral, 2 is positive, and 3 is negative.
1 is positive, 2 is neutral, and 3 is negative.
1 is positive, 2 is negative, and 3 is neutral.
1 is negative, 2 is neutral, and 3 is positive.
1
Name: ________________________
____
ID: A
5) An electron moving in the +y direction, at right angles to a magnetic field, experiences a magnetic
force in the -x direction. The direction of the magnetic field is in the
-x direction.
+x direction.
+y direction.
-z direction.
+z direction.
A)
B)
C)
D)
E)
____
6) A charged particle moving along the +x-axis enters a uniform magnetic field pointing along the
+z-axis. A uniform electric field is also present. Due to the combined effect of both fields, the
particle does not change its velocity. What is the direction of the electric field?
A) along the -y-axis
B) along the +y-axis
C) along the -x-axis
D) along the +x-axis
E) along the -z-axis
____
7) We observe that a moving charged particle experiences no magnetic force. From this we can
definitely conclude that
A) no magnetic field exists in that region of space.
B) the particle must be moving parallel to the magnetic field.
C) the particle is moving at right angles to the magnetic field.
D) either no magnetic field exists or the particle is moving parallel to the field.
E) either no magnetic field exists or the particle is moving perpendicular to the field.
____
8) A charged particle moves with a constant speed through a region where a uniform magnetic field is
present. If the magnetic field points straight upward, the magnetic force acting on this particle will
be strongest when the particle moves
A) straight upward.
B) straight downward.
C) in a plane parallel to Earth's surface.
D) upward at an angle of 45° above the horizontal.
____
9) At a particular instant, an electron moves toward the east in a uniform magnetic field that is directed
straight downward. The magnetic force that acts on it is
A) zero.
B) upward.
C) toward the north.
D) toward the south.
E) downward.
2
Name: ________________________
ID: A
____ 10) An electron has an initial velocity to the south but is observed to curve upward as the result of a
magnetic field. This magnetic field must have a component
A) to the west.
B) to the east.
C) upward.
D) downward.
E) to the north.
____ 11) A proton has an initial velocity to the south but is observed to curve upward as the result of a
magnetic field. This magnetic field must have a component
A) to the west.
B) to the east.
C) upward.
D) downward.
E) to the north.
____ 12) A charged particle is injected into a uniform magnetic field such that its velocity vector is
perpendicular to the magnetic field lines. Ignoring the particle's weight, the particle will
A) move in a straight line.
B) follow a spiral path.
C) move along a parabolic path.
D) follow a circular path.
____ 13) A rectangular coil, with corners labeled ABCD, has length L and width w. It is placed between the
poles of a magnet, as shown in the figure If there is a current I flowing through this coil in the
direction shown, what is the direction of the force acting on section BC of this coil?
A)
B)
C)
D)
E)
perpendicular to and into the page
perpendicular to and out of the page
in the direction of the magnetic field
in the opposite direction of the magnetic field
The force is zero.
3
Name: ________________________
ID: A
____ 14) When the switch is closed in the circuit shown in the figure, the wire between the poles of the
horseshoe magnet deflects upward. From this you can conclude that the left end of the magnet is
A) a north magnetic pole.
B) a south magnetic pole.
C) There is not enough information given to answer the question.
____ 15) Two long parallel wires placed side-by-side on a horizontal table carry identical current straight
toward you. From your point of view, the magnetic field at a point exactly between the two wires
A) points upward.
B) points downward.
C) points toward you.
D) points away from you.
E) is zero.
____ 16) A wire lying in the plane of this page carries a current directly toward the top of the page. What is
the direction of the magnetic force this current produces on an electron that is moving perpendicular
to the page and outward from it on the left side of the wire?
A) perpendicular to the page and towards you
B) perpendicular to the page and away from you
C) toward the top of the page
D) toward the bottom of the page
E) The force is zero.
____ 17) The magnetic field at a distance of 2 cm from a long straight current-carrying wire is 4 μT. What is
the magnetic field at a distance of 4 cm from this wire?
A) 2 μT
B) 4 μT
C) 6 μT
D) 8 μT
E) 10 μT
4
Name: ________________________
ID: A
____ 18) A long straight wire carrying a 4-A current is placed along the x-axis as shown in the figure. What is
the direction of the magnetic field at a point P due to this wire?
A)
B)
C)
D)
E)
into the plane of the page
out of the plane of the page
along the -x-axis
along the +x-axis
along the +y-axis
____ 19) Which one of the following statements is correct?
A) When a current-carrying wire is in your right hand, with your thumb in the
direction of the current, your fingers point opposite to the direction of the
magnetic field lines.
B) When a current-carrying wire is in your right hand, with your thumb in the
direction of the current, your fingers point in the direction of the magnetic field
lines.
C) When a current-carrying wire is in your left hand, with your thumb in the
direction of the current, your fingers point in the direction of the magnetic field
lines.
____ 20) A vertical wire carries a current vertically downward. To the east of this wire, the magnetic field
points
A) north.
B) east.
C) south.
D) down.
____ 21) When a ferromagnetic material is placed in an external magnetic field, the net magnetic field of its
magnetic domains becomes
A) smaller.
B) zero.
C) larger.
22.2 Problems
22) A proton moving at 5.0 × 104 m/s horizontally enters a region where a magnetic field of 0.12 T is
present, directed vertically downward. What magnitude force acts on the proton due to this field?
(e = 1.60 × 10-19 C)
5
Name: ________________________
ID: A
23) An electron traveling toward the magnetic north with speed 400 km/s enters a region where the
earth's magnetic field has the magnitude 5.0 × 10-5 T and is directed downward at 45° below
horizontal. What magnitude magnetic force acts on the electron? (e = 1.60 × 10-19 C)
____ 24) A proton travels at a speed of 5.0 × 107 m/s through a 1.0-T magnetic field. What is the magnitude
of the magnetic force on the proton if the angle between the proton's velocity and the magnetic field
vector is 30°? (e = 1.60 × 10-19 C)
A) 2.0 × 10-14 N
B) 4.0 × 10-14 N
C) 2.0 × 10-12 N
D) 4.0 × 10-12 N
25) A proton, with mass 1.67 × 10-27 kg and charge +1.6 × 10-19 C, is sent with velocity
in
the +x direction into a region where there is a uniform electric field of magnitude
in the +y
direction. What must be the magnitude and direction of the uniform magnetic field in the region if
the proton is to pass through undeflected? Assume that the magnetic field has no x component and
neglect gravitational effects.
____ 26) A proton is projected with a velocity of 7.0 km/s into a magnetic field of 0.60 T perpendicular to the
motion of the proton. What is the magnitude of the magnetic force that acts on the proton? (e = 1.60
× 10-19 C)
A) 0 N
B) 3.4 × 10-16 N
C) 4.2 × 10-16 N
D) 13 × 10-16 N
E) 6.7 × 10-16 N
27) In the figure, a small particle of charge -1.9 x
C and mass
has speed
as it enters a region of uniform magnetic field. The particle is initially traveling
perpendicular to the magnetic field and is observed to travel in the semicircular path shown with
radius R = 5.0 cm. Find the magnitude and direction of the magnetic field in the region.
6
Name: ________________________
ID: A
____ 28) A straight 1.0-m long wire is carrying a current. The wire is placed perpendicular to a magnetic field
of strength 0.20 T. If the wire experiences a force of 0.60 N, what is the current in the wire?
A) 2.0 A
B) 1.0 A
C) 3.0 A
D) 4.0 A
E) 5.0 A
____ 29) A long straight wire carrying a 4-A current is placed along the x-axis as shown in the figure. What is
the magnitude of the magnetic field at a point P, located at y = 2 cm, due to the current in this wire?
(μ0 = 4π × 10-7 T • m/A)
A)
B)
C)
D)
E)
20 μT
30 μT
40 μT
50 μT
60 μT
____ 30) At point P the magnetic field due to a long straight wire carrying a current of 2.0 A is 1.2 µT. How
far is P from the wire? (μ0 = 4π × 10-7 T • m/A)
A) 11 cm
B) 22 cm
C) 33 cm
D) 44 cm
E) 55 cm
____ 31) A very long thin wire produces a magnetic field of
wire. What is the magnitude of the current? (μ0 = 4π ×
A) 1.0 mA
B) 2.0 mA
C) 4000 mA
D) 3100 mA
7
10-7
at a distance of
T • m/A)
from the
Name: ________________________
ID: A
____ 32) Two long parallel wires that are 0.40 m apart carry currents of 10 A in opposite directions. What is
the magnetic field strength in the plane of the wires at a point that is 20 cm from one wire and 60 cm
from the other? (μ0 = 4π × 10-7 T • m/A)
A) 3.3 µT
B) 6.7 µT
C) 33 µT
D) 67 µT
33) An ideal solenoid having 200 turns and carrying a current of 2.0 A is 25 cm long. What is the
magnitude of the magnetic field at the center of the solenoid? (μ0 = 4π × 10-7 T • m/A)
____ 34) An ideal solenoid of length 10 cm consists of a wire wrapped tightly around a wooden core. The
magnetic field strength is
inside the solenoid. If the solenoid is stretched to
force to it, what does the magnetic field become?
A) 1.6 T
B) 10.0 T
C) 20 T
D) 4.0 T
by applying a
____ 35) An ideal solenoid is wound with 470 turns on a wooden form that is 4.0 cm in diameter and 50 cm
long. The windings carry a current in the sense shown in the figure. The current produces a magnetic
field of magnitude
at the center of the solenoid. What is the current I in the solenoid
-7
windings? (μ0 = 4π × 10 T • m/A)
A)
B)
C)
D)
E)
3.5 A
3.0 A
2.6 A
4.3 A
3.9 A
8
ID: A
Magnetism
Answer Section
1)
2)
3)
4)
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8)
9)
10)
11)
12)
13)
14)
15)
16)
17)
18)
19)
20)
21)
22)
ANS:
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ANS:
C
C
A
E
E
B
D
C
D
A
B
D
E
B
E
E
A
B
B
C
C
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
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PTS:
PTS:
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
REF:
REF:
REF:
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REF:
REF:
REF:
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REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
Var: 1
Var: 1
Var: 1
Var: 1
Var: 1
Var: 1
Var: 1
Var: 1
Var: 1
Var: 1
Var: 1
Var: 1
Var: 1
Var: 1
Var: 1
Var: 1
Var: 1
Var: 1
Var: 1
Var: 1
Var: 1
9.6 × 10-16 N
PTS: 1
23) ANS:
REF: Var: 1
2.3 × 10-18 N
PTS: 1
24) ANS: D
25) ANS:
REF: Var: 1
PTS: 1
REF: Var: 1
3.4 × 10-2 T, +z direction
PTS: 1
26) ANS: E
27) ANS:
REF: Var: 50+
PTS: 1
REF: Var: 1
0.26 T, into the paper
28)
29)
30)
31)
PTS:
ANS:
ANS:
ANS:
ANS:
1
C
C
C
A
REF:
PTS:
PTS:
PTS:
PTS:
Var: 50+
1
1
1
1
REF:
REF:
REF:
REF:
1
Var: 1
Var: 1
Var: 1
Var: 27
ID: A
32) ANS: B
33) ANS:
PTS: 1
REF: Var: 1
REF: Var: 1
PTS: 1
PTS: 1
REF: Var: 50+
REF: Var: 50+
2.0 mT
PTS: 1
34) ANS: A
35) ANS: A
2
Magnetism [Answer Strip]
ID: A
E
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5)
A 10)
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B
_____
6)
B 11)
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B 14)
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B 18)
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C
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1)
C
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2)
E 15)
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D 12)
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B 19)
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D
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7)
A
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3)
E 16)
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E 13)
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C
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8)
C 20)
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A 17)
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E
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4)
D
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9)
C 21)
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Magnetism [Answer Strip]
C 28)
_____
ID: A
B 32)
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D 24)
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C 29)
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A 34)
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E 26)
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A 35)
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C 30)
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A 31)
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