Name: ________________________ Class: ___________________ Date: __________
Exam 2--PHYS 202--S14
Multiple Choice
Identify the choice that best completes the statement or answers the question.
1. A farad is the same as a:
a. N/C
b. V/C
c. V/J
d. C/V
e. J/V
2. The plate areas and plate separations of five
parallel plate capacitors are
capacitor 1: area A, separation d
capacitor 2: area 2A, separation 2d
capacitor 3: area 2A, separation d/2
capacitor 4: area A/2, separation 2d
capacitor 5: area A, separation d/2
4. Consider this circuit. What is the charge on C 2?
a. 6 C
b. 24 C
c. 4 C
d. 2 C
e. 12 C
5. A parallel-plate capacitor initially has a potential
difference of 200 V and is then disconnected from
the charging battery. If the area of the plates is
now doubled, what is the new value of the voltage?
Rank these according to their capacitances, least to
greatest.
a. 4, 1 and 2 tie, then 5, 3
b. 5,4,3,2,1
c. 3, 5, 1 and 2 tie, 4
d. 1,2,3,4,5
e. 5, 3 and 4 tie, then 1, 2
3. Two identical capacitors are connected in series
and two, each identical to the first, are connected in
parallel. The equivalent capacitance of the series
connection _________is the equivalent capacitance
of parallel connection.
a.
b.
c.
d.
e.
a. 400 V
b. 800 V
c. 100 V
d. 200 V
6. Let Q denote charge, V denote potential difference,
and U denote stored energy. Of these
quantities, capacitors in parallel must have the
same:
a. Q only
b. Q & U only
c. U only
d. V & U only
e. V only
twice
four times
half
one-fourth
the same as
1
Name: ________________________
7. Consider this circuit. All three capacitors are
identical. What is the voltage across C 3?
12. Current is a measure of:
a.
b.
c.
d.
speed with which a charge moves past a point
force that moves a charge past a point
energy used to move a charge past a point
amount of charge that moves past a point per
unit time
e. resistance to the movement of a charge past a
point
13. If the potential difference across a resistor is
doubled:
a. only the current is doubled
b. only the current is halved
c. only the resistance is doubled
d. only the resistance is halved
e. both the current and resistance are doubled
14. Consider these 2 wires. Wire A has four times the
area and twice the length of wire B. How do their
resistances compare?
C2
C1
C3
12 V
a. 8 V
b. 12 V
c. 3V
d. 4 V
e. 6 V
8. Two capacitors with CA greater than CB and are
connected in series with a battery. Which of the
following is true?
a. There is more charge stored on CB.
b. There is the same charge stored on each
capacitor.
c. There is the same potential difference across
both capacitors.
d. There is more charge stored on CA.
9. Current has units:
a. kilowatt hour
b. ohm
c. coulomb
d. volt
e. coulomb/second
10. The conventional direction of current in this circuit
would be:
1
R
4 B
1
 RB
8
1
 RB
2
 4R B
 2R B
a.
RA 
b.
RA
c.
RA
d.
e.
RA
RA
15. For a certain diode, the current flows unimpeded in
one direction. For current in the opposite direction,
the ______________________.
a. resistance is zero.
b. resistance is very large.
c. voltage is very small.
d. current is very large.
e. resistivity is very small.
a. clockwise
b. counter-clockwise
c. there is not current
11. Which of these has the greater resistance, a
incandescent light bulb (60 W) or a bathroom
heater (1000 W)?
a. both the same
b. heater
c. bulb
2
Name: ________________________
Problem
16. Consider this circuit and complete the table.
3
Name: ________________________
17. (15 pts) Two capacitors, C 1 and C2, are in series. Each capacitor has plates with area 0.006 m 2 that are separated
by 1.77x10-8 m. One of the capacitors, C2, has a dielectric with a constant of 2.
What is the equivalent capacitance of these capacitors?
Ceq=________
If they are connected to a 10V battery, what is the charge on each?
Q1=________
Q2=________
If you remove the dielectric, does the charge on each capacitor increase, decrease, or stay the same. Circle the
correct response below.
Q1 increases, decreases or stays the same?
Q2 increases, decreases or stays the same?
4
Name: ________________________
18. (10 pts) Your bathroom heater has a power of 1200 W and operates at 120 V.
a) What is the resistance of the heater?
b) What is the current through the heater?
c) If the heater runs for 3 minutes, what amount of charge travels through the heater?
d) Entergy charges $0.10 per kilowatt-hour. How much does it cost to run this heater for 2 hours?
5
Name: ________________________
19. ( 10 pts) A 0.20-m-long metal rod has a radius of
1.0 cm and a resistance of 3.2  105 . What is the
resistivity of the metal?
20. (10 pts) Consider this circuit. Complete the table.
What are the units for resistivity?
.
6
ID: A
Exam 2--PHYS 202--S14
Answer Section
MULTIPLE CHOICE
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
D
A
D
B
C
E
D
B
E
A
C
D
A
C
B
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
PROBLEM
16. ANS:
.
PTS: 1
17. ANS:
.
PTS: 1
18. ANS:
.
PTS: 1
19. ANS:
.
PTS: 1
20. ANS:
.
PTS: 1
1