ame: ________________________ Class: ___________________ Date: __________
ID: A
Exam 1--PHYS 102--Spring 2010
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
____
1. If the charge on q1 has a magnitude of 3 nC, what is the charge on q 2?
a. -9 nC
d. 18 nC
b. 9 nC
e. -12 nC
c. -18 nC
2. Consider these 2 separate arrangements of insulating materials. If q 3 has a negative charge, what is the
charge of q1?
a.
b.
positive
neutral
c.
d.
1
negative
not enough information
ame: ________________________
____
____
____
____
ID: A
3. Two charges experience an electric force of 20 N. If the distance between the 2 charges is doubled, what is
the new force on the charges?
a. 10 N
c. 20 N
b. 40 N
d. 5 N
4. Consider these 2 charges. Where on the x-axis can a third positive charge be placed such that the net force
on that charge is zero?
a. to the left of -Q
b. in between -Q and 3Q
5. Which of these is not an allowable charge?
c.
d.
to the right of 3Q
it is not possible
c. 2.4x10-19 C
a. -1.6x10-19 C
-19
d. 25C
b. 8.0x10 C
6. Which vector in this figuure best represents the direction of the electric field at the point P due to the two
charges?
a.
b.
c.
A
B
C
d.
e.
2
D
E
ame: ________________________
____
____
ID: A
7. 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. up
c. to the right
b. down
d. to the left
8. A capacitor is hooked up to a battery with voltage of 12 V. After charging the capacitor, the battery is
removed. What is the voltage across the capacitor if the area of the plates is doubled?
a.
b.
c.
18 V
0V
6V
d.
e.
3
24 V
12 V
ame: ________________________
____
ID: A
9. 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.
E≠0,V=0
E=0, V≠0
____ 10. The following graph is for potential (V) versus position (x). If a
direction will it move?
a.
b.
c.
to the left
to the right
it will be stationary
d.
e.
4
proton is released at point x=A, what
it will oscillate around point A
none of these
ame: ________________________
ID: A
____ 11. What is the voltage across the circled capacitor in this figure?
a. 5 V
d. 1 V
b. 2.5 V
e. 3.33 V
c. 10 V
____ 12. Two wires, A and B, are made of the same metal and have equal length, but the resistance of wire A is four
times the resistance of wire B. How do their diameters compare?
d. dA=½dB
a. dA=4dB
b. dA=2dB
e. dA=¼dB
c. dA=dB
____ 13. Which of these has the greater resistance, a incandescent light bulb (60 W) or a bathroom heater?
a. both the same
c. bulb
b. heater
____ 14. When you apply a potential of 3 V to a particular electrical device, the current in 2 A. When you apply 6V,
the current is 3 A. Is this device Ohmic or Non-Ohmic?
a. Non-Ohmic
c. Neither
b. Ohmic
d. Not enough information
5
ame: ________________________
ID: A
Problem
15. (10 pts) The following graph shows the potential due to an electric field. Sketch the x-component of the
electric field (in the blank axes below) for this situation.
6
ame: ________________________
ID: A
16. (15 pts) The potential due to an electric field is given by this function:
V(x,y,z) = xy 2 − 3yx + 4y
An electron is at x=1 and y=1 m. What is the magnitude and direction of the force on the electron due to the
electric field?
.
7
ame: ________________________
ID: A
17. (15 pts) Three 2 µC charges are assembled in the following configuration.
a) How much work does it take to assemble the configuration?
b) What is the potential at the charge labeled with the “ ×”?
8
ame: ________________________
ID: A
18. (20 pts) Consider the following circuit:
a) What is the equivalent capacitance? ____________
b) What is the charge on C 1?
____________
c) What is the potential across C 2?
____________
d) What is the potential across C 3?
____________
e) What is the potential across C 5?
____________
f) What is the energy stored by C 5?
____________
9
ame: ________________________
ID: A
19. (10 pts) A 100 W light bulb operates at 120 volts.
a) What is the resistance of the light bulb?
b) What is the current through the light bulb?
c) In 10 seconds, how much charge has traveled through the light bulb’s filament?
10
ID: A
Exam 1--PHYS 102--Spring 2010
Answer Section
MULTIPLE CHOICE
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
B
A
D
A
C
D
D
C
D
C
A
D
C
A
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
PROBLEM
15. ANS:
PTS: 1
16. ANS:
.
PTS: 1
17. ANS:
.
PTS: 1
18. ANS:
.
PTS: 1
19. ANS:
.
PTS: 1
1