Download Conceptual Practice Problems for PHYS 1112 In-Class Exam #2A+2B

Physics 1112
Spring 2009
University of Georgia
Instructor: HBSchüttler
Conceptual Practice Problems
for
PHYS 1112 In-Class Exam #2A+2B
Thu. Apr. 9, 2009, 11:00am-12:15pm and 2:00pm-3:15pm
CP 3.01: If a wire of some length L and a circular cross-section of diameter D has a
resistance of 36 kΩ, what will be the resistance of a wire made from the same material, at
the same temperature, of length 3L and the same diameter D ?
(A)
(B)
(C)
(D)
(E)
4 kΩ
12 kΩ
24 kΩ
72 kΩ
108 kΩ
CP 3.02: If a wire of some length L and a circular cross-section of diameter D has a
resistance of 36 kΩ, what will be the resistance of a wire made from the same material, at
the same temperature, of the same length L and diameter 3D ?
(A)
(B)
(C)
(D)
(E)
4 kΩ
12 kΩ
24 kΩ
72 kΩ
108 kΩ
CP 3.03: If a wire of some length L and a circular cross-section of diameter D has a
resistance of 36 kΩ, what will be the resistance of a wire made from the same material, at
the same temperature, of length 18L and diameter 3D ?
(A)
(B)
(C)
(D)
(E)
4 kΩ
12 kΩ
24 kΩ
72 kΩ
108 kΩ
CP 3.04: Three different circuits, X, Y and Z, are built with the same three resistors,
R1 > 0, R2 > 0, and R3 > 0, and the same battery of battery voltage E, as shown in Fig.
3.04. Compare and rank the magnitude of the currents I1 through R1 , observed in the three
1
Physics 1112
Spring 2009
University of Georgia
Instructor: HBSchüttler
different circuits.
Fig. 3.04
Io
I2
I3
E
I1
(X)
(A)
(B)
(C)
(D)
(E)
Io
R2
R3
R1
I2
Io
R2
I1
E
I3
R1
I3
R3
I1
E
I2
R3
(Y)
R1
R2
(Z)
Ranking cannot be determined from information given.
I1 (X) > I1 (Z) > I1 (Y )
I1 (Y ) > I1 (X) > I1 (Z)
I1 (Y ) > I1 (Z) > I1 (X)
I1 (Z) > I1 (Y ) > I1 (X)
CP 3.05: Three different circuits, X, Y and Z, are built with the same three resistors,
R1 > 0, R2 > 0, and R3 > 0, and the same battery of battery voltage E, as shown in Fig.
3.04. Compare and rank the magnitude of the voltage drops V3 across resistor R3 , observed
in the three different circuits.
(A)
(B)
(C)
(D)
(E)
Ranking cannot be determined from information given.
V3 (X) > V3 (Z) > V3 (Y )
V3 (Y ) > V3 (X) > V3 (Z)
V3 (Y ) > V3 (Z) > V3 (X)
V3 (Z) > V3 (Y ) > V3 (X)
CP 3.06: Three different circuits, X, Y and Z, are built with the same three resistors,
R1 > 0, R2 > 0, and R3 > 0, and the same battery of battery voltage E, as shown in Fig.
3.04. Compare and rank the equivalent resistance Req (from R1 , R2 and R3 combined) in
these three circuits.
2
Physics 1112
Spring 2009
(A)
(B)
(C)
(D)
(E)
University of Georgia
Instructor: HBSchüttler
Ranking cannot be determined from information given.
Req (X) < Req (Z) < Req (Y )
Req (Y ) < Req (X) < Req (Z)
Req (Y ) < Req (Z) < Req (X)
Req (Z) < Req (Y ) < Req (X)
CP 3.07: Three different circuits, X, Y and Z, are built with the same three resistors,
R1 > 0, R2 > 0, and R3 > 0, and the same battery of battery voltage E, as shown in Fig.
3.04. Compare and rank the magnitude of the total battery current Io observed in the three
circuits.
(A)
(B)
(C)
(D)
(E)
Ranking cannot be determined from information given.
Io (X) > Io (Z) > Io (Y )
Io (Y ) > Io (X) > Io (Z)
Io (Y ) > Io (Z) > Io (X)
Io (Z) > Io (Y ) > Io (X)
CP 3.08: Three different circuits, X, Y and Z, are built with the three resistors, R1 > 0,
R2 > 0, and R3 > 0, and a battery of battery voltage E, as shown in Fig. 3.04.
Let Io > 0, I1 > 0, I2 > 0, and I3 > 0 denote the currents through the battery, R1 , R2 , and
R3 , respectively. Let V1 > 0, V2 > 0, and V3 > 0 denote the voltage drops across R1 , R2 ,
and R3 , respectively.
Which of the following statements is false ?
(A)
(B)
(C)
(D)
(E)
In
In
In
In
In
circuit
circuit
circuit
circuit
circuit
X: Io = I1 and V1 + V3 = E − V2 .
Y : Io = I1 + I2 and V1 = V2 + V3 .
Z: Io = I1 + I3 and V2 = V1 + V3 .
Y : I1 + I2 = I3 + I1 and V2 = E − V3 .
Z: I1 = I2 and V1 /V2 = R1 /R2 .
CP 3.09: Three different circuits, X, Y and Z, are built with the three resistors, R1 > 0,
R2 > 0, and R3 > 0, and a battery of battery voltage E, as shown in Fig. 3.04.
Let Io > 0, I1 > 0, I2 > 0, and I3 > 0 denote the currents through the battery, R1 , R2 , and
R3 , respectively. Let V1 > 0, V2 > 0, and V3 > 0 denote the voltage drops across R1 , R2 ,
and R3 , respectively.
Which of the following statements is false ?
(A) In circuit X: I2 + I3 = I3 + I1 and V3 /E = R3 /(R1 + R2 + R3 ).
(B) In circuit Y : Io = I1 + I3 and V1 /R1 = E[1/(R3 + R2 ) + 1/R1 ].
(C) In circuit Z: I1 (R1 + R2 ) = I3 R3 and V3 = V1 + V2 .
3
Physics 1112
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Instructor: HBSchüttler
(D) In circuit Y : I1 /(R2 + R3 ) = I2 /R1 and V1 = E.
(E) In circuit Z: 1/R3 + 1/(R1 + R2 ) = Io /E and V1 /R1 = E/(R1 + R2 ).
CP 3.10: In a Kirchhoff rule analysis, current arrows have been assigned to the I1 -, I2 - and
I3 -branches of a circuit for which a fragment (i.e., not the whole circuit) is shown in Fig.
3.10. Also assume that the voltrage drop across R is defined as
VR ≡ Va − Vb
where Va and Vb are the electric potential values at points a and b shown in Fig. 3.10
I1
I2
Fig. 3.10
a
I3
R
b
Suppose R = 10Ω and I1 = +5A and I2 = +2A for the arrow directions shown in Fig. 3.10.
What is VR and in which direction is the current actually flowing through R ?
(A)
(B)
(C)
(D)
(E)
VR
VR
VR
VR
VR
= +70V
= −70V
= +30V
= −30V
= +30V
and
and
and
and
and
|I3 |
|I3 |
|I3 |
|I3 |
|I3 |
flows
flows
flows
flows
flows
from
from
from
from
from
a to b.
b to a.
a to b.
b to a.
b to a.
CP 3.11: In a Kirchhoff rule analysis, current arrows have been assigned to the I1 -, I2 - and
I3 -branches of a circuit for which a fragment (i.e., not the whole circuit) is shown in Fig.
3.10. Also assume that the voltrage drop across R is defined as
VR ≡ Va − Vb
4
Physics 1112
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where Va and Vb are the electric potential values at points a and b shown in Fig. 3.10
Suppose R = 10Ω and I1 = +2A and I2 = +5A for the arrow directions shown in Fig.
3.10.
What is VR and in which direction is the current actually flowing through R ?
(A)
(B)
(C)
(D)
(E)
VR
VR
VR
VR
VR
= +70V
= −70V
= +30V
= −30V
= +30V
and
and
and
and
and
|I3 |
|I3 |
|I3 |
|I3 |
|I3 |
flows
flows
flows
flows
flows
from
from
from
from
from
a to b.
b to a.
a to b.
b to a.
b to a.
CP 3.12: In a Kirchhoff rule analysis, current arrows have been assigned to the I1 -, I2 - and
I3 -branches of a circuit for which a fragment (i.e., not the whole circuit) is shown in Fig.
3.10. Also assume that the voltrage drop across R is defined as
VR ≡ Va − Vb
where Va and Vb are the electric potential values at points a and b shown in Fig. 3.10
Suppose R = 10Ω and I1 = −5A and I2 = +2A for the arrow directions shown in Fig.
3.10.
What is VR and in which direction is the current actually flowing through R ?
(A)
(B)
(C)
(D)
(E)
VR
VR
VR
VR
VR
= +70V
= −70V
= +30V
= −30V
= +30V
and
and
and
and
and
|I3 |
|I3 |
|I3 |
|I3 |
|I3 |
flows
flows
flows
flows
flows
from
from
from
from
from
a to b.
b to a.
a to b.
b to a.
b to a.
CP 3.13: In a Kirchhoff rule analysis, current arrows have been assigned to the I1 -, I2 - and
I3 -branches of a circuit for which a fragment (i.e., not the whole circuit) is shown in Fig.
3.10. Also assume that the voltrage drop across R is defined as
VR ≡ Va − Vb
where Va and Vb are the electric potential values at points a and b shown in Fig. 3.10
Suppose R = 10Ω and VR = −20V and I2 = −5A for the arrow directions shown in Fig.
3.10.
What is I1 ? Is the current |I1 | actually flowing towards or away from point a ?
(A) I1 = +7A with |I1 | flowing towards a.
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Physics 1112
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(B)
(C)
(D)
(E)
I1
I1
I1
I1
= −7A
= +3A
= −3A
= −3A
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Instructor: HBSchüttler
with
with
with
with
|I1 |
|I1 |
|I1 |
|I1 |
flowing
flowing
flowing
flowing
away from a.
towards a.
away from a.
towards a.
CP 3.14: In a Kirchhoff rule analysis, current arrows have been assigned to the I1 -, I2 - and
I3 -branches of a circuit for which a fragment (i.e., not the whole circuit) is shown in Fig.
3.10. Also assume that the voltrage drop across R is defined as
VR ≡ Va − Vb
where Va and Vb are the electric potential values at points a and b shown in Fig. 3.10
Suppose |VR | = 120V and I1 = +5A and I2 = −7A for the arrow directions shown in
Fig. 3.10.
What is R and what is the sign of VR ?
(A)
(B)
(C)
(D)
(E)
R = 10 Ω and VR > 0.
R = 10 Ω and VR < 0.
R = 60 Ω and VR > 0.
R = 60 Ω and VR < 0.
R = −60 Ω and VR < 0.
6
Physics 1112
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CP 3.15: A molecular ion beam containing four different types of ions, called P , Q, R and
S here, enters a uniform magnetic field, as shown in Fig. 3.15, with B 6= 0 above the lower
~ perpendicular to, and pointing out of, the plane of the drawing. The
horizontal line, and B
incident beam, below the lower horizontal line, is in the plane of the drawing.
Fig. 3.15
B (out)
P
Q
R
S
B=0
~
From the semicircular ion trajectories in the B-field
shown in Fig. 3.15, find the signs (+ or
−) of the charges qP , qQ , qR and qS of each of the four different ion types in the beam.
(A)
(B)
(C)
(D)
(E)
P :+,
P :+,
P :−,
P :+,
P :−,
Q:+,
Q:−,
Q:+,
Q:−,
Q:−,
R:−,
R:−,
R:+,
R:+,
R:+,
S:−,
S:+,
S:−,
S:−,
S:+,
CP 3.16: A molecular ion beam containing four different types of ions, called P , Q, R and
S here, enters a uniform magnetic field, as shown in Fig. 3.15, with B 6= 0 above the lower
~ perpendicular to, and pointing out of, the plane of the drawing. The
horizontal line, and B
incident beam, below the lower horizontal line, is in the plane of the drawing.
~
The diameters of the semicircular ion trajectories in the B-field,
denoted by dP , dQ , dR and
dS , respectively are observed to be in a ratio of
dP : dQ : dR : dS = 3 : 2 : 1 : 4 ,
as indicated in Fig. 3.15. Assume all four ion types carry the same amount of charge per
~
ion, |q|, and they all enter the B-field
with the same speed v. What is the ratio of the four
ion masses, denoted by mP , mQ , mR and mS , respectively ?
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Physics 1112
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(A)
(B)
(C)
(D)
mP
mP
mP
mP
:
:
:
:
mQ
mQ
mQ
mQ
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Instructor: HBSchüttler
:
:
:
:
mR
mR
mR
mR
:
:
:
:
mS
mS
mS
mS
=3 : 2 : 1 : 4 .
√
√
√
√
= 3 : 2 : 1 : 4 .
= 13 : 12 : 11 : 14 .
= √13 : √12 : √11 : √14 .
(E) mP : mQ : mR : mS = 9 : 4 : 1 : 16 .
CP 3.17: A molecular ion beam containing four different types of ions, called P , Q, R and
S here, enters a uniform magnetic field, as shown in Fig. 3.15, with B 6= 0 above the lower
~ perpendicular to, and pointing out of, the plane of the drawing. The
horizontal line, and B
incident beam, below the lower horizontal line, is in the plane of the drawing.
~
The diameters of the semicircular ion trajectories in the B-field,
denoted by dP , dQ , dR and
dS , respectively are observed to be in a ratio of
dP : dQ : dR : dS = 3 : 2 : 1 : 4 ,
as indicated in Fig. 3.15. Assume all four ion types carry the same amount of charge per
~
ion, |q|, and they all enter the B-field
with the same kinetic energy K. What is the ratio of
the four ion masses, denoted by mP , mQ , mR and mS , respectively ?
(A)
(B)
(C)
(D)
mP
mP
mP
mP
:
:
:
:
mQ
mQ
mQ
mQ
:
:
:
:
mR
mR
mR
mR
:
:
:
:
mS
mS
mS
mS
=3 : 2 : 1 : 4 .
√
√
√
√
= 3 : 2 : 1 : 4 .
= 13 : 12 : 11 : 14 .
= √13 : √12 : √11 : √14 .
(E) mP : mQ : mR : mS = 9 : 4 : 1 : 16 .
CP 3.18: In a series of four magnetic deflection experiments, referred to as experiment P ,
Q, R and S, respectively, a beam of electrons, all of the same kinetic energy K, enters a
uniform magnetic field, as shown in Fig. 3.15, with B 6= 0 above the lower horizontal line
~ perpendicular to the plane of the drawing. The incident electron beam, below the
and B
lower horizontal line, is in the plane of the drawing.
In each of these four experiments, a different magnetic field strength and field direction is
~ is pointing out of the plane of the
used. In two of the experiments (which ones ?) B
drawing, i.e., in the direction indicated in Fig. 3.15; in the other two experiments (which
~ is pointing into the plane of the drawing, i.e., opposite to the direction
ones ?) B
indicated in Fig. 3.15.
The diameters of the four semicircular electron trajectories denoted by dP , dQ , dR and dS ,
respectively are observed to be in a ratio of
dP : dQ : dR : dS = 3 : 2 : 1 : 4 ,
as indicated in Fig. 3.15. Find the ratio of the four magnetic field strengths, denoted by
BP , BQ , BR and BS , respectively, that were used in these four deflection experiments ?
8
Physics 1112
Spring 2009
(A)
(B)
(C)
(D)
BP
BP
BP
BP
:
:
:
:
University of Georgia
Instructor: HBSchüttler
BQ
BQ
BQ
BQ
:
:
:
:
BR
BR
BR
BR
:
:
:
:
BS
BS
BS
BS
=3 : 2 : 1 : 4 .
√
√
√
√
= 3 : 2 : 1 : 4 .
= 13 : 21 : 11 : 41 .
= √13 : √12 : √11 : √14 .
(E) BP : BQ : BR : BS = 9 : 4 : 1 : 16 .
CP 3.19: A very thin circular metallic ring lies in the y − z-plane and it is centered at the
coordinate origin O ≡ (0, 0, 0), as shown in Fig. 3.19. A current I flows around the ring in
~ ≡ (Bx , By , Bz )
the direction indicated in panel (B) of Fig. 3.19. The magnetic field vector B
produced by this current at the center of the ring has cartesian components Bx , By and Bz
~ by:
given in terms of the field strength B ≡ |B|
(A)
(B)
y
Fig. 3.19
z
I
x
y
y
z
x-y-Plane View
z
x
x
y
y-z-Plane View
(A) (Bx , By , Bz ) = (+B, 0, 0)
(B) (Bx , By , Bz ) = (−B, 0, 0)
(C) (Bx , By , Bz ) = (0, √B2 , √B2 )
(D) (Bx , By , Bz ) = (0, −B, 0)
(E) (Bx , By , Bz ) = (0, 0, +B)
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Physics 1112
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CP 3.20: A very thin circular metallic ring lies in the x − z-plane and it is centered at the
coordinate origin O ≡ (0, 0, 0), as shown in Fig. 3.20. A current I flows around the ring in
~ ≡ (Bx , By , Bz )
the direction indicated in panel (B) of Fig. 3.20. The magnetic field vector B
produced by this current at the center of the ring has cartesian components Bx , By and Bz
~ by:
given in terms of the field strength B ≡ |B|
(A)
(B)
y
Fig. 3.20
z
I
x
x
y
z
x-y-Plane View
z
x
y
x
x-z-Plane View
(A) (Bx , By , Bz ) = (+B, 0, 0)
(B) (Bx , By , Bz ) = (−B, 0, 0)
(C) (Bx , By , Bz ) = (0, √B2 , √B2 )
(D) (Bx , By , Bz ) = (0, −B, 0)
(E) (Bx , By , Bz ) = (0, 0, +B)
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CP 3.21: A very thin circular ring lies initially in the x − z-plane and it is centered at the
coordinate origin O ≡ (0, 0, 0), as shown in Fig. 3.21. A current I flows around the ring in
the direction indicated in panel (B) of Fig. 3.21.
(A)
(B)
z
Fig. 3.21
z
I
y
x
z
x
y-z-Plane View
z
y
y
x
x-z-Plane View
Suppose this ring is now rotated by 45o around the x-axis, with the rotation direction being
counter-clockwise in the y−z-plane view shown in panel (A) of Fig. 3.21. The magnetic
~ ≡ (Bx , By , Bz ) produced by the current I at the center of the ring, after the
field vector B
o
~ by:
45 -rotation, is then given in terms of the field strength B ≡ |B|
B
√ ,√
)
(A) (Bx , By , Bz ) = (0, −B
2
2
√ , −B
√ )
(B) (Bx , By , Bz ) = (0, −B
2
2
(C) (Bx , By , Bz ) = (0, √B2 , √B2 )
(D) (Bx , By , Bz ) = (0, −B, 0)
(E) (Bx , By , Bz ) = (0, 0, +B)
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CP 3.22: A very thin circular ring lies initially in the x − y-plane and it is centered at the
coordinate origin O ≡ (0, 0, 0), as shown in Fig. 3.22. A current I flows around the ring in
the direction indicated in panel (B) of Fig. 3.22.
(A)
(B)
z
Fig. 3.22
y
I
y
x
z
x
y-z-Plane View
y
y
z
x
x-y-Plane View
Suppose this ring is now rotated by 45o around the x-axis, with the rotation direction being
clockwise in the y−z-plane view shown in panel (A) of Fig. 3.22. The magnetic field
~ ≡ (Bx , By , Bz ) produced by the current I at the center of the ring, after the
vector B
o
~ by:
45 -rotation, is then given in terms of the field strength B ≡ |B|
B
√ ,√
)
(A) (Bx , By , Bz ) = (0, −B
2
2
√ , −B
√ )
(B) (Bx , By , Bz ) = (0, −B
2
2
(C) (Bx , By , Bz ) = (0, √B2 , √B2 )
(D) (Bx , By , Bz ) = (0, −B, 0)
(E) (Bx , By , Bz ) = (0, 0, +B)
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CP 3.23: Two very thin circular rings, labeled 1 and 2 in the following, with radii R1 and
R2 , respectively, and R1 > R2 , are both centered at the coordinate origin O ≡ (0, 0, 0), as
shown in Fig. 3.23.
Ring 1 lies in the y − z-plane with current I1 flowing around the ring in the direction indicated in panel (B) of Fig. 3.23. Ring 2 lies in the x − z-plane with current I2 flowing around
the ring in the direction indicated in panel (C) of Fig. 3.23.
Fig. 3.23
(A)
(B)
(C)
y
z
z
I1
1
2
x
I2
2
2
y
x
1
1
y
z
x-y-Plane View
z
x
z
y
x
y
y-z-Plane View
x
x-z-Plane View
Let B1 > 0 and B2 > 0 denote the magnetic field strengths produced at the origin O by only
~ ≡ (Bx , By , Bz )
I1 alone and only I2 alone, respectively. The total magnetic field vector B
produced by both currents at the origin O is then given by:
(A)
(B)
(C)
(D)
(E)
(Bx , By , Bz ) = (0 , B1 + B2 ,
(Bx , By , Bz ) = (B1 − B2 , 0 ,
(Bx , By , Bz ) = (−B2 , −B1 ,
(Bx , By , Bz ) = (+B2 , −B1 ,
(Bx , By , Bz ) = (+B1 , −B2 ,
0)
0)
0)
0)
0)
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CP 3.24: Two very thin circular rings, labeled 1 and 2 in the following, with radii R1 and
R2 , respectively, and R1 > R2 , are both centered at the coordinate origin O ≡ (0, 0, 0), as
shown in Fig. 3.24.
Ring 1 lies in the x − z-plane with current I1 flowing around the ring in the direction indicated in panel (B) of Fig. 3.24. Ring 2 lies in the x − y-plane with current I2 flowing around
the ring in the direction indicated in panel (C) of Fig. 3.24.
Fig. 3.24
(A)
(B)
(C)
z
z
y
I1
1
2
y
I2
2
2
x
x
1
1
z
x
z
y
y-z-Plane View
y
y
x
z
x-z-Plane View
x
x-y-Plane View
Let B1 > 0 and B2 > 0 denote the magnetic field strengths produced at the origin O by only
~ of the total magnetic field
I1 alone and only I2 alone, respectively. The strength B ≡ |B|
~ ≡ (Bx , By , Bz ) produced by both currents at the origin O is then given by:
vector B
(A)
(B)
(C)
(D)
(E)
B
B
B
B
B
= B1 + B2
= (B1 B2 )1/2
= (B12 + B22 )1/2
= |B1 − B2 |
= (B12 B22 )1/4
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University of Georgia
Instructor: HBSchüttler
CP 3.25: A very long thin straight wire running along the z-axis through the coordinate
origin, carries a current I1 in the +z-direction, as shown in Fig. 3.25.
Fig. 3.25
P
y
(A)
(B)
(E)
(C)
(D)
x
I1
y
x-y-Plane View
z
x
Which arrow drawn at point P in the x − y-plane could correctly represent the magnetic
~ produced by I1 at P ?
field vector B
(A)
(B)
(C)
(D)
(E)
CP 3.26: A very long thin straight wire running along the z-axis through the coordinate
origin, carries a current I1 in the +z-direction, as shown in Fig. 3.25.
Suppose a second wire running parallel to the z-axis through point P carries a current
I2 (not shown in Fig. 3.25) in the −z-direction. Which arrow drawn at point P in the
x − y-plane could correctly represent the magnetic force vector F~ on the I2 -wire due to the
magnetic field produced by I1 ?
(A)
(B)
(C)
(D)
(E)
15
Physics 1112
Spring 2009
University of Georgia
Instructor: HBSchüttler
CP 3.27: A very long thin straight wire running parallel to the z-axis and cutting through
the x-axis, carries a current I1 in the −z-direction, as shown in Fig. 3.27.
Fig. 3.27
(C)
y
(D)
(B)
(E)
(A)
I1
P
x
y
x-y-Plane View
z
x
Which arrow drawn at point P in the x − y-plane could correctly represent the magnetic
~ produced by I1 at P ?
field vector B
(A)
(B)
(C)
(D)
(E)
CP 3.28: A very long thin straight wire running parallel to the z-axis and cutting through
the x-axis, carries a current I1 in the −z-direction, as shown in Fig. 3.27.
Suppose a second wire running parallel to the z-axis through point P carries a current
I2 (not shown in Fig. 3.27) in the −z-direction. Which arrow drawn at point P in the
x − y-plane could correctly represent the magnetic force vector F~ on the I2 -wire due to the
magnetic field produced by I1 ?
(A)
(B)
(C)
(D)
(E)
16
Physics 1112
Spring 2009
University of Georgia
Instructor: HBSchüttler
CP 3.29: Two very long thin straight wires running parallel to the z-axis and cutting
through the y-axis and through the x-axis, respectively, carry currents I1 in the +z-direction
and I2 in the −z-direction, respectively, as shown in Fig. 3.29.
Fig. 3.29
(C)
y
I1
(D)
(B)
(E)
P
(A)
I2
x
y
x-y-Plane View
z
x
Which arrow drawn at point P in the x − y-plane could correctly represent the total mag~ produced jointly by I1 and I2 at P ?
netic field vector B
(A)
(B)
(C)
(D)
(E)
17
Physics 1112
Spring 2009
University of Georgia
Instructor: HBSchüttler
CP 3.30: Two very long thin straight wires running parallel to the z-axis and cutting
through the x-axis and through the coordinate origin, respectively, carry currents I1 in the
−z-direction and I2 in the +z-direction, respectively, as shown in Fig. 3.30.
Fig. 3.30
y
(D)
(C)
(E)
(B)
(A)
I2
I1
P
x
y
x-y-Plane View
z
x
Which arrow drawn at point P in the x − y-plane could correctly represent the total mag~ produced jointly by I1 and I2 at P ?
netic field vector B
(A)
(B)
(C)
(D)
(E)
18