Name: ________________________ Class: ___________________ Date: __________
ID: A
Exam 1--PHYS 102--Spring 2008
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
____
1. In this figure, a ball made of insulating material is attracted to a positively charged rod. What is the charge of
the ball?
a. negative
c. either positive or negative
b. positive
d. not enough information
2. This figure shows two charged particles separated by a distance of 2 cm. What is the force on Q 1?
a.
b.
25 N
-1100 N
c.
d.
1
13 N
1100 N
Name: ________________________
ID: A
____
3. What is the ratio of q 1/q2?
____
a. -1/2
c. 1/2
b. 2
d. -2
4. In this figure, which arrow best represents the direction of the net force on the particle whose charge is +Q?
a.
b.
c.
1
2
3
d.
e.
2
4
5
Name: ________________________
____
____
____
ID: A
5. An alpha particle (+2e) is sent at a velocity of 10 6 m/s toward a gold nucleus (+79e) What is the magnitude of
the electric force acting on the gold nucleus when it is 1x10-12 m from the alpha particle?
a. 8x1025 N
d. 0.002 N
b. 0 N
e. 0.04 N
17
c. 2x10 N
6. A proton is accelerated from rest in an electric field of 100 V/m. What is the velocity of the proton after 2
seconds? (The mass of a proton is 1.67x10 -27 kg.)
c. 1.9x1010 m/s
a. 3.3x10-25 m/s
9
b. 9.6x10 m/s
d. 4.8x109 m/s
7. A styrofoam ball is covered with conducting paint and has a mass of 0.01 kg. If an electric field of 100 N/C
is sufficient to levitate the ball (i.e. balance the gravitational force), what is the charge on the ball?
a.
b.
980 µC
0.098 µC
c.
d.
3
9800 µC
9.8 µC
Name: ________________________
____
____
ID: A
8. Two charges experience an electric force of 2 N between them. If you increase one charge by a factor of 4
(ie, 4q) and increase the distance between them by a factor of 4 (4r), what is the new force between the
charges?
a. 2 N
d. 0.25 N
b. 0.5 N
e. 32 N
c. 8 N
9. In this figure, two charges are separated by a certain distance. Where must another positive charge be placed
in order to create a net force of zero for all charges?
a.
b.
to the right of -Q
to the left of +Q
c.
d.
in between +Q and -Q
it is impossible to create a net force of
zero
____ 10. Positive and negative particles are separated by a certain distance. They are released. After their release,
which has the larger velocity?
a. the positive particle
c. the negative particle
b. both have the same velocity
d. not enough information
____ 11. In this figure, a ball made of conducting material is attracted to a positively charged rod. What is the charge
of the ball?
a.
b.
neutral
either positive or negative
c.
d.
4
positive
none of these
Name: ________________________
ID: A
____ 12. What is the energy stored in the capacitor C 1? (p is for pico, which equals 10 -12)
a.
b.
500 J
1000 J
c.
d.
5
1 nJ
0.5 nJ
Name: ________________________
ID: A
____ 13. These six charges are at the corner of an equilateral hexagon. What pair of statements best describes the
electric field and potential at a point in the center of the hexagon, equidistant from each of the charges?
a. E=0, V≠0
c. E≠0, V≠0
d. E=0, V=0
b. E≠0,V=0
____ 14. A proton and electon are in a constant E-field as shown. You release an electron and proton at a point
equidistant between the plates. Which particle has a higher velocity when they strike the plates?
a.
b.
neither, they have the same velocity
proton
c.
d.
6
not enough information
electron
Name: ________________________
ID: A
____ 15. In which of the following diagrams is the potential along the x-axis equal to zero?
a. a
d. none of these
b. b
e. all of these
c. c
____ 16. What is the potential at the point A if q1=2.0 µC and q2=-1.0 µC?
a.
b.
400,000 V
120,000 V
c.
d.
7
180,000 V
12 V
Name: ________________________
ID: A
____ 17. The following graph is for potential (V) versus position (x). If a proton is released at point A, what direction
will it move?
a. to the left
c. it will be stationary
b. to the right
d. none of these
____ 18. Three charged particles have a charge of +2 µC each and are arranged at the apexes of an equilateral triangle
as shown. The sides of the triangle are 0.1 m in length. How much work is required to assemble these
charges?
a.
b.
1J
0.2 J
c.
d.
8
-2 J
1x10-6 J
Name: ________________________
ID: A
____ 19. What is the charge on the 3.00 mF capacitor?
a.
b.
28.8 mC
810. mC
c.
d.
9
54.0 mC
6.00 mC
Name: ________________________
ID: A
____ 20. What is the equivalent capacitance of this circuit?
4
µF
3
b. 4.33 µF
d. 2.00 µF
____ 21. In this circuit, what is the potential across the 24 µF capacitor?
a.
9.00 µF
c.
a.
b.
1.2 V
18 V
c.
d.
10
4.5 V
29 V
Name: ________________________
ID: A
____ 22. What must be done to a capacitor in order to increase the amount of charge it can hold (assuming it has a
constant voltage)?
I. Decrease the area of the plates
II. Decrease separation between the plates
III. Insert a dielectric between the plates
IV. Increase the separation between the plates
a. III
d. II & III
b. I & III
e. I & IV
c. III & IV
____ 23. A capacitor has plates with area 21x10 -12 m2 and has a capacitance of 60x10 -15 F. What is the separation
between the plates?
a. 3.1x10-9 m
b. 3.5 m
____ 24. The answer to this question is “A.”
a. A
b. B
c.
d.
1.3x10-24 m
3.5x10-6 m
c.
d.
C
D
11
ID: A
Exam 1--PHYS 102--Spring 2008
Answer Section
MULTIPLE CHOICE
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