Name: ________________________
Exam 2--PHYS 102--Spring 2016
Multiple Choice
Identify the choice that best completes the statement or answers the question.
1. What is the equivalent capacitance of this circuit?
3. What is the charge on the 6 µF capacitor?
a.
b.
c.
d.
e.
a.
b.
c.
d.
9 µF
5 µF
16 µF
2 µF
4. Which of these statements is necessarily true?
I. The voltage across a voltmeter is very large.
II. The current through a voltmeter is very small.
III. The resistance of a voltmeter is very small.
IV. A voltmeter should be connected in parallel.
a. II & IV
b. I & III
c. I & II
d. III & IV
e. IV only
2. For the previous circuit, what is the voltage across
the 1µF capacitor?
a.
b.
c.
d.
e.
1.3 µC
2 µC
24 µC
108 µC
72 µC
3V
4V
6V
8V
12 V
5. A battery has an internal resistance of 1 Ω . When it
provides a current of 2 A, the potential across the
battery is 10 V. What is the ideal electromotive
force provided by the battery?
a.
b.
c.
d.
1
12 V
20 V
5V
30 V
6. A 3 V potential difference is maintained across a
10 Ω resistor for 2 minutes. How many electrons
pass through the material?
a. 2.25x1020
b. 0.3
c. 60
d. 36
e. 3.75x1018
10. A current of 10 A flows through a wire of length 1
m and cross-sectional area 5x10 -8 m2. The potential
across the wire is 20 V. From this table of
resistivities, select the material of the wire:
Material
Copper
Silver
Gold
Tungsten
Iron
7. Consider this circuit. What is the current through
the resistor?
a.
b.
c.
d.
a.
b.
c.
d.
e.
3A
36 A
0.25 A
4A
Copper
Silver
Gold
Tungsten
Iron
11. Consider this circuit; R 1 has a voltage of 8V?
What is the voltage of the battery?
8. A flat iron is marked “120 V,600 W.” What is the
resistance of this device?
a.
b.
c.
d.
e.
Resistivity(Ohm-m)
1.7x10-8
1.59x10-8
2.44x10-8
5.5x10-8
10.0x10-8
24 Ω
72,000 Ω
3000 Ω
5Ω
0.2 Ω
9. In your house, two lightbulbs operate at 120 V, but
one has a power rating of 25 W while the other has
a power rating of 100 W. Which one has the
greater current flowing through it?
a. both have same current
b. 100 W bulb
c. 25 W bulb
d. not enough information
a.
b.
c.
d.
e.
2
8V
10 V
12 V
16 V
24 V
14. Which of these statements about a household
circuit is true:
12. Which of these resistors has the smallest current?
I. The household circuit is a parallel circuit.
II. All devices in a household circuit operate at the
same voltage.
III. As you add more devices to a household circuit,
the total current increases.
IV. A circuit breaker turns off if the total current
exceeds some predetermined value.
a.
b.
c.
d.
e.
R1
R2
R3
R5
not enough information
a.
b.
c.
d.
e.
15. On a circuit breaker, you have a 2400 W heater, a
120 W light bulb, and a 240 W radio. When you
add a 360 W blender, the circuit breaker turns off.
Assume all the devices operate at 120 V. Which of
these is the maximum allowed current for the
breaker?
13. Consider this circuit.What is the current through
the 4Ω resistor?
a.
b.
c.
d.
a.
b.
c.
d.
e.
II & III
I, II, & III
III & IV
I & II
all of these are correct
0.5 A
1A
2A
3A
8A
30 A
25 A
15 A
10 A
16. What purpose does the GFCI serve?
a. Protect the electrical system from too much
current
b. Provide an alternate path to ground for faulty
devices
c. Turn off the circuit if the total current exceeds
a safe value
d. Protect the user from severe electrical shock
3
17. Which of these rules for resistors in parallel is
correct?
19. Consider a series RC circuit for which R = 1.0 MΩ,
C=5.0 µF, and ε=10.0 V. Initially the capacitor has
no charge. When connected to the battery and
resistor, what is the charge on the capacitor after
5.0 seconds?
I. Resistors in parallel must have the same current.
II. Resistors in parallel must have the same voltage.
III. For resistors in parallel, the total voltage across
the resistors is equal to the sum of the voltage
across the individual resistors.
IV. For resistors in parallel, the equivalent
resistance is always less than the smallest resistor.
a.
b.
c.
d.
e.
a.
b.
c.
d.
e.
II only
II & III
II & IV
I & III
I & IV
18. Which of these plots shows the
for a charging capacitor?
150 µC
50 µC
40 µC
30 µC
0 µC
20. Which of these rules for resistors in series is not
correct?
voltage vs time
I. Resistors in series must have the same current.
II. Resistors in series must have the same voltage.
III. For resistors in series, the total voltage across
the resistors is equal to the sum of the voltage
across the individual resistors.
IV. For resistors in series, the equivalent resistance
is equal to the sum of the indiviual resistors
a. II & III
b. I & III
c. II only
d. II & IV
e. I & IV
a.
b.
c.
d.
21. Three resistors are in series with a 36 V battery: 2
Ω , 4 Ω, and 6 Ω. What is the potential across the
6 Ω resistor?
a. 1 V
b. 36 V
c. 12 V
d. 18 V
e. 6 V
A
B
C
D
4
22. Consider this circuit. Which of these equations is
correct?
24. What is the current through the 2 Ωresistor?
a.
b.
c.
d.
e.
a.
b.
c.
d.
3-2I1+6-6I2-5=0
3+2I1+5+6I2=0
I1+I2+I3=0
5+6I2-6=0
18 A
3A
9A
5A
12 A
25. You measure a voltage of 4 V across a resistor of 2
Ω. In 2 minutes, how much charge has passed
through the resistor?
23. For the circuit above, what is the direction and
magnitude of I2?
2
a.
A, to the right
3
11
b.
A, to the left
6
c. 0 A
1
d.
A, to the left
6
a.
b.
c.
d.
e.
120 C
2C
16 C
240 C
4C
26. Who is Dr. Young’s favorite student?
a. Mia Roberts
b. Jacques Richard
c. Ayanna Clurare
d. Joseph Tolstoy
e. Me!!!
5
ID: A
Exam 2--PHYS 102--Spring 2016
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.
26.
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:
ANS:
D
B
C
A
A
A
D
A
B
E
B
C
A
E
B
D
C
B
D
C
D
D
D
B
D
E
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:
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
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
S16
S16
S16
S16
S16
S16
S16
S16
S16
S16
S16
S16
S16
S16
S16
S16
S16
S16
S16
S15, S16
S16
S16
S16
S16
S16
1