Download Physics 112

Physics 112
Exam 4
Spring 2006
Name_________________
Physics 112
Spring 2006
Exam 4
Thursday, May 4
Directions:
This 2-houers exam consists of twenty six multiple-choice questions.
The questions on this test are not in order of difficulty.
You must mark all of your answers on both your test and the answer sheet.
In marking the multiple choice bubble sheet use a number 2 pencil. Do not use ink. If
you did not bring a pencil, ask for one. Fill in the appropriate circles completely. If you
need to change any entry, you must completely erase your previous entry.
Carefully read each question and its five possible answers. Select one and only one
answer for each question. Choose the answer that is closest to the correct one.
Be sure to write you name on every sheet.
You have a sheet in the back of the test that you may use for any extra rough work.
When you are finished with the exam, place all exam materials, including the bubble
sheet, the exam itself, and scratch paper that you used for the exam, in your folder and
return the folder.
Good luck!
Page 1 of 10
Physics 112
Exam 4
Spring 2006
61. A 5.0 μC charge is placed at the 0 cm mark of a meter stick and a -4.0 μC charge is
placed at the 50 cm mark. What is the electric field at the 30 cm mark?
A.
B.
C.
D.
E.
4.0 × 105 N/C
5.0 × 105 N/C
9.0 × 105 N/C
1.4 × 106 N/C
7.6 × 106 N/C
62. Two 3.00-μC charges are at the ends of a meter stick. Find the electrical potential for
the center of the meter stick.
A.
B.
C.
D.
E.
0
120 V
2.70 × 104 V
5.40 × 104 V
1.08 × 105 V
63. Five identical capacitors, 50 μF each, are connected in parallel, and are then
connected to a battery of 3 V. What charge is stored in each capacitor?
A.
B.
C.
D.
E.
30 μC
60 μC
83 μC
150 μC
750 μC
64. A coffee maker, which draws 13.5 A of current, has been left on for 10 min. What is
the net number of electrons that have passed through the coffee maker?
A.
B.
C.
D.
E.
1.5 × 1022
5.1 × 1022
1.6 × 1019
1.8 × 103
8.1 × 103
Page 2 of 10
Physics 112
Exam 4
Spring 2006
65. A 500-W device is connected to a 120-V ac power source. What is the peak voltage
across this device?
A.
B.
C.
D.
E.
4.2 V
5.9 V
120 V
170 V
220 V
66. What is the total resistance of the circuit below?
A.
B.
C.
D.
E.
80 Ω
55 Ω
50 Ω
35 Ω
25 Ω
67. An electric field of 1.60 kV/m and magnetic field of 0.400 T act on a moving electron
to produce no net force. Calculate the minimum speed of the electron.
A.
B.
C.
D.
E.
2.00*103 m/s
4.00*103 m/s
6.00*103 m/s
8.00*103 m/s
2.00*102 m/s
68. A current carrying circular loop of wire lies flat on a table top. When viewed from
above, the current moves around the loop in a counterclockwise sense. What is the
direction of the magnetic field caused by this current, inside the loop?
The magnetic field
A. circles the loop in a clockwise direction
B. circles the loop in a counterclockwise direction
C. points straight up
D. points straight down
E. points North
Page 3 of 10
Physics 112
Exam 4
Spring 2006
69. A long solenoid has 200 turns/cm and carries current 1.00A. A sphere of the radius
0.50 cm is placed inside the solenoid. Find the magnetic flux through the sphere.
A.
B.
C.
D.
E.
0
1.6*10-7 T*m2
4.0*10-8 T*m2
8.0*10-8 T*m2
1.6*10-8 T*m2
70. What is the direction of the induced current in the circular loop due to the decreasing
current shown below?
I decreasing
A.
B.
C.
D.
E.
counterclockwise
clockwise
the direction of the current is periodically changing
induced current is equal to zero
there is not enough information to answer the quastion
71. The coil of a generator has 50 loops and a cross-sectional area of 0.25 m2. What is
the maximum emf generated by this generator if it is spinning with an angular
velocity of 4.0 rad/s in a 2.0 T magnetic field?
A.
B.
C.
D.
E.
50 V
100 V
200 V
400 V
600 V
72. An object is located 2.6 m in front of a plane mirror. The image formed by the mirror
appears to be
A.
B.
C.
D.
E.
1.3 m in front of the mirror
On the mirror's surface
1.3 m behind the mirror's surface
2.6 m behind the mirror's surface
2.6 m in front of the mirror
Page 4 of 10
Physics 112
Exam 4
Spring 2006
73. A concave mirror with a radius of 20 cm creates a real image 30 cm from the mirror.
What is the object distance?
A.
B.
C.
D.
E.
20 cm
15 cm
7.5 cm
5.0 cm
3.0 cm
74. At the first maxima on either side of the central bright spot in a double-slit
experiment, light from each opening arrives
A.
B.
C.
D.
E.
in phase
45° out of phase
90° out of phase
180° out of phase
none of the given answers
75. Monochromatic light from a distant source is incident on a slit 0.75 mm wide. On a
screen 2.00 m away, the distance from the central maximum of the diffraction pattern
to the first minimum is measured to be 1.35 mm. Calculate the wavelength of the
light.
A.
B.
C.
D.
E.
506 nm
555 nm
610 nm
709 nm
1012 nm
76. What is the minimum thickness of a nonreflecting film coating (n = 1.30) on a glass
lens (n = 1.50) for wavelength 500 nm?
A.
B.
C.
D.
E.
250 nm
192 nm
167 nm
125 nm
96.2 nm
Page 5 of 10
Physics 112
Exam 4
Spring 2006
77. What is the energy difference between the second excited state and first excited state
of an electron in the “box” of size L=1nm?
A.
B.
C.
D.
E.
1.9 eV
1.1 eV
0.6 eV
0.3 eV
0.2 eV
78. If l = 4, which one of the following is a possible quantum number for n?
A.
B.
C.
D.
E.
0
1
2
4
8
79. A neutral atom has an electron configuration of 1s22s22p63s23p2. What is its atomic
number?
A.
B.
C.
D.
E.
5
11
14
20
28
80. You have 16 kg of a radioactive sample with a certain half-life of 30 years. How
much is left after 90 years?
A.
B.
C.
D.
E.
8 kg
4 kg
2 kg
1 kg
nothing
81. When a target nucleus is bombarded by an appropriate beam of particles, it is possible
to produce
A.
B.
C.
D.
E.
A less massive nucleus, but not a more massive one.
A more massive nucleus, but not a less massive one.
A nucleus with smaller atomic number, but not one with a greater atomic number.
A nucleus with greater atomic number, but not one with a smaller atomic number.
A nucleus with either greater or smaller atomic number.
Page 6 of 10
Physics 112
Exam 4
Spring 2006
82. What is the Q-value for radioactive decay reactions?
A.
B.
C.
D.
E.
Q<0
Q>0
Q=0
Sign of Q depends on the nucleus
Sign of Q depends on the external conditions
83. What is the nucleus that results in the reaction given below?
2
n 16
8 O  ?1 H
A.
17
8
O
B.
15
8
O
C.
15
8
N
D.
17
7
N
E.
15
7
N
84. How does the total mass of the fission fragments compare to the mass of the original
nucleus in a fission reaction?
A.
B.
C.
D.
E.
Fission fragments have more mass
Fission fragments have less mass
Fission fragments have the same mass
It depends on the nucleus
It depends on the external conditions
85. A cyclotron operates at 10 MHz. What magnetic field is needed to accelerate
protons?
A.
B.
C.
D.
E.
0.12 T
0.25 T
0.66 T
1.50 T
2.35 T
86. What is the wavelength for a beam of 1.4 GeV electrons?
A.
B.
C.
D.
E.
8.9 × 10-14 m
8.9 × 10-15 m
8.9 × 10-16 m
8.9 × 10-17 m
8.9 × 10-18 m
Page 7 of 10
Physics 112
Exam 4
Spring 2006
Scratch Paper (intentionally left blank).
Page 8 of 10
Physics 112
Exam 4
Spring 2006
Record Sheet
You may fill in this sheet with your choices, detach it and take it with you after the exam
for comparison with the posted answers
61
71
81
62
72
82
63
73
83
64
74
84
65
75
85
66
76
86
67
77
68
78
69
79
70
80
Page 9 of 10
Physics 112
Exam 4
Spring 2006
Answer key
61
71
D. 1.4 × 106 N/C
62
B. 100 V
72
E. 1.08 × 105 V
63
D. 2.6 m behind the
mirror's surface
73
D. 150 μC
B. 15 cm
64
74
B. 5.1 × 1022
65
81
E. A nucleus with either
greater or smaller atomic
number
82
B. Q>0
83
E.
75
B. Fission fragments
have less mass
85
A. 506 nm
66
76
C. 50 Ω
B. 4.00*10 m/s
77
A. 1.9 eV
C. points straight up
78
E. 8
3
68
69
C. 0.66 T
86
E. 96.2 nm
67
N
84
A. in phase
D. 170 V
15
7
C. 8.9 × 10-16 m
79
A. 0
70
A. counterclockwise
C. 14
80
C. 2 kg
Page 10 of 10