ame: ________________________
Exam 1--PHYS 102--Spring 2011
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1. An object has a mass of 2.0x10 -6 kg and is placed in a uniform electric field of 640 N/C,
which is directed downward.
a.
b.
____
-0.031 µC
-3.2x108 C
The object floats. What is the charge of the object?
c.
d.
130 µC
+0.031 µC
2. A proton is accelerated by a constant electric field of magnitude 220 N/C; the proton is
moving in the same direction as the electric field. How far does the proton move in 1x10 -6
s?
a.
b.
1100 m
1.4x10-6 m
c.
d.
1
19 m
0.011 m
____
3. This figure shows two charges and their electric field lines. If the charge on the left has a magnitude of 6 µC,
what is the sign and magnitude of the right charge?
____
a. +3 µC
d. -3 µC
e. -12 µC
b. -6 µC
c. +12 µC
4. What is the net force on the center charge (q=+48 µC) in this figure?
____
a. 190 N to the left
b. 0 N
c. 530 N to the right
5. Which of these is not a valid charge?
a.
b.
-1.6x10-19 C
7.0x10-19 C
d.
e.
260 N to the left
93 N to the right
c.
d.
-4 C
8.0x10-19 C
2
____
____
6. Consider this configuration of charges. Which vector best represents the net force acting on the rightmost
charge?
a. a
d. d
b. b
e. e
c. c
7. In this figure, 2 charges are separated by a distance d. The point A is equidistant between the two charges.
The point B is a distance d/2 from the right charge. Where is the electric field the greatest in magnitude?
a.
b.
A
B
c.
d.
3
both A & B have the same magnitude E
not enough information; it depends on d
____
____
8. Which best describes the work required to move the charge along the dotted line in this figure?
a. zero work
c. positive work
b. negative work
d. not enough information
9. This figure shows how particles a and b respond to one another and, separately, how a and c respond to one
another. Which of these statements is true:
a.
b.
a & c are opposite charges
b & c are like charges
c.
d.
4
a & b are like charges
b & c are opposite charges
____ 10. 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 more kinetic energy when they strike the plates?
a. neither, they have the same KE
c. electron
b. not enough information
d. proton
____ 11. Two charges are arranged on the vertices of this equilateral triangle as shown. If Q=2.0 µC, what is the
potential at the top, where the smiley face sits?
a.
b.
-72,000 V
0.25 V
c.
d.
5
+110,000 V
-36,000 V
____ 12. In this figure, an electron sits between two charged plates. The electron moves to the right in response to the
electric field. What is the direction of the electric field in between the plates?
a. to the left
c. down
b. up
d. to the right
____ 13. In which of the following diagrams is the potential along the x-axis equal to zero?
a.
b.
c.
a
b
c
d.
e.
6
none of these
all of these
____ 14. Consider this figure. If Q=1 C, how much work is required to assemble the charges into this configuration?
a. 120 J
c. 6.3x1010 J
-9
b. 3.4x10 J
d. 3.2x1010 J
____ 15. This figure shows a positive charge with concentric circles surrounding it. At what point(s) is the potential at
its greatest value?
a.
b.
c.
A
B
C
d.
e.
7
D
C&D
____ 16. What is the equivalent capacitance of this circuit?
a. 2.0 µF
c. 14 µF
d. 12 µF
b. 7.6 µF
____ 17. For the circuit in the previous figure, what is the potential across the 2.0 µF capacitor?
a.
b.
2V
8V
c.
d.
8
6V
4V
____ 18. Consider this circuit. What is the charge on the 3.0 µF capacitor?
3.0 µF
6.0 µF
2.0 µF
12 V
a. 36 µC
c. 130 µC
d. 4.0 µC
b. 24 µC
____ 19. For the circuit in the previous figure, what is the charge on the 2.0 µF capacitor?
a. 2.0 µC
c. 12 µC
d. 6.0 µC
b. 24 µC
____ 20. 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.
b.
E=0, V=0
E≠0,V=0
c.
d.
9
E≠0, V≠0
E=0, V≠0
____ 21. A capacitor consists of 2 metal plates with an area of 0.4 m 2 each. The plates are separated by a distance of
1x10-6 m. A piece of paper is between the two plates; this paper has a dielectric constant of 1.5. What is the
capacitance of the capacitor?
c. 60. µF
a. 3.5 µF
d. 5.3 µF
b. 4.0 µF
____ 22. A parallel-plate capacitor initially has a potential difference of 200 V and is then disconnected from the
charging battery. If the plate area is now doubled (without changing Q), what is the new value of the
voltage?
a. 100 V
c. 400 V
b. 800 V
d. 200 V
____ 23. Consider this circuit. What is the current through the resistor?
a. 3 A
c. 36 A
b. 0.25 A
d. 4 A
____ 24. Which of the following best describes the purpose of resistors?
a. turn a circuit on or off.
c. store electrical energy.
b. act as a timing device within a circuit.
d. slow the flow of electricity.
____ 25. The answer to this question is “B.” Bubble “B” on your scantron.
a.
b.
A
B
c.
d.
10
C
D
ID: A
Exam 1--PHYS 102--Spring 2011
Answer Section
MULTIPLE CHOICE
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
A
D
C
C
B
E
A
A
D
A
D
A
D
C
E
A
C
B
B
B
D
A
D
D
B
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1