Download Current and Resistance Practice Multiple Choice Identify the choice

Current and Resistance Practice
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1. How is current affected if the time interval over which the charge passes through a given area decreases while
the amount of charge remains the same?
a. The current increases.
b. The current decreases.
c. The current initially increases and then is gradually restored.
d. The current is not affected.
____
2. The current in an electron beam in a cathode-ray tube is 7.0  10
s?
a. 2.8  10 C
c. 3.5  10 C
b. 5.6  10 C
d. 5.3  10 C
____
3. The amount of charge that moves through the filament of a lightbulb in 2.00 s is 2.67 C. What is the current in
the lightbulb?
a. 5.34 A
c. 0.835 A
b. 1.33 A
d. 0.417 A
____
4. When electrons move through a metal conductor,
a. they move in a straight line through the conductor.
b. they move in zigzag patterns because of repeated collisions with the vibrating metal
atoms.
c. the temperature of the conductor decreases.
d. they move at the speed of light in a vacuum.
____
5. A lightbulb has a resistance of 240  when operating at 120 V. What is the current in the lightbulb?
a. 2.0 A
c. 0.50 A
b. 1.0 A
d. 0.20 A
____
6. Which of the following wires would have the greatest resistance?
a. an aluminum wire 10 cm in length and 3 cm in diameter
b. an aluminum wire 5 cm in length and 3 cm in diameter
c. an aluminum wire 10 cm in length and 5 cm in diameter
d. an aluminum wire 5 cm in length and 5 cm in diameter
____
7. Which of the following is the best description of a schematic diagram?
a. uses pictures to represent the parts of a circuit
b. determines the location of the parts of a circuit
c. shows the parts of a circuit and how the parts connect to each other
d. shows some of the parts that make up a circuit
____
8. Three resistors connected in series have potential differences across them labeled V , V , and V . Which
of the following expresses the potential difference taken over the three resistors together?
a. Vt = V1 + V2 + V3
c. Vt = V1 = V2 = V3
A. How much charge hits the screen in 5.0
b.
____
Vt =
d.
Vt =
9. Three resistors connected in parallel carry currents labeled I , I , and I . Which of the following expresses the
total current I in the combined system?
a. It = I1 + I2 + I3
c. It = I1 = I2 = I3
b.
d.
It =
It =
____ 10. Three resistors with values of 3.0 , 6.0 , and 12  are connected in parallel. What is the equivalent
resistance of this combination?
a. 0.26 
c. 9.0 
b. 1.7 
d. 21 
____ 11. The symbol used to represent resistance in a schematic diagram is
a. two straight lines.
b. a single line that is broken and has a bend in it.
c. one straight line.
d. a zigzag line.
e. none of the above
____ 12. When resistors are put in series next to each other, their overall resistance is
a. the same as the resistance of one of the resistors.
b. larger than the resistance of any individual resistor.
c. smaller than the resistance of any of the resistors.
____ 13. As more lamps are put into a parallel circuit, the overall current in the main (through the battery) circuit
a. increases.
b. stays the same.
c. decreases.
____ 14. Compared to the resistance of two resistors connected in series, the same two resistors connected in parallel
have
a. less resistance.
b. more resistance.
c. the same resistance.
____ 15. When one light bulb in a parallel circuit containing several light bulbs burns out, the other light bulbs
a. do not burn at all.
b. burn brighter.
c. burn the same as before.
____ 16. In a simple parallel circuit
a. voltage across each branch is the same.
b. current through each resistor is inversely proportional to the resistance.
c. current is divided at each branch.
d. all of the above
e. none of the above
____ 17. Two lamps, one with a thick filament and one with a thin filament, are connected in parallel to a battery. The
voltage is greater across the lamp with the
a. thin filament.
b. thick filament.
c. Both voltages are the same.
____ 18. Two lamps, one with a thick filament and one with a thin filament, are connected in series to a battery. The
voltage is greater across the lamp with the
a. thin filament.
b. thick filament.
c. Voltage is the same for both.
____ 19. In order for there to be a flow of charge from one place to another, there must be a
a. conductor, such as a wire, connecting the two places.
b. potential difference between the two places.
c. Both A and B above
____ 20. An example of a voltage source is
a. a dry cell.
b. a generator.
c. a car battery.
d. rubbing a rubber rod with fur.
e. all of the above
____ 21. Electrical resistance in a wire depends on the wire's
a. thickness.
b. conductivity.
c. length.
d. all of the above
e. none of the above
____ 22. What is the equivalent resistance for the resistors in the figure shown above?
a. 25 
c. 7.5 
b. 10.0 
d. 5.0 
Short Answer
23. What is electrical potential energy?
24. What is the source of the energy produced by a battery?
25. With regard to electric current, what is resistance?
26. Draw a schematic diagram that contains three resistors and one battery.
27. Current is not carried in the circuit shown in the schematic diagram above. Explain why this is so.
28. In the circuit shown above, what will happen when the switch is closed? Explain.
Problem
29. A bolt of lightning discharges 9.6 C in 5.5  10
s. What is the average current during the discharge?
30. How much time is required for 41.34 C of charge to move through an electric juicer if the current through the
juicer is 1.48 A?
31. How much current is in a resistor of 227  if the potential difference across the resistor is 145 V?
32. A potential difference of 3.6 V is placed across a resistor, producing a current of 14.3 A. What is the
resistance of the resistor?
33. A 1.4 k resistor has 0.012 A of current in it. What is the potential difference across the resistor?
34. A 4.7  10  resistor carries 1.52  10
A of current. What potential difference is across the resistor?
35. Three resistors with values of 17 , 23 , 9 , respectively, are connected in series. What is their equivalent
resistance?
36. A current of 0.12 A passes through a 5.1  resistor. The resistor is connected in series with a 9.1 V battery
and an unknown resistor. What is the resistance value of the unknown resistor?
37. Three resistors with values of 11 , 15 , 22 , respectively, are connected in parallel. What is their
equivalent resistance?
38. A 60-V potential difference is applied across a parallel combination of a 10-ohm and a 20-ohm resistor. What
is the current in the 10-ohm resistor?
39. What is the equivalent resistance for the resistors in the figure shown above?
40. How much current is in one of the 10  resistors in the diagram shown above?
Current and Resistance Practice
Answer Section
MULTIPLE CHOICE
1. ANS: A
2. ANS: C
Given
I = 7.0  10
t = 5.0 s
PTS: 1
DIF: II
OBJ: 17-3.1
DIF: IIIA
OBJ: 17-3.1
DIF: IIIA
PTS: 1
OBJ: 17-3.1
DIF: I
OBJ: 17-3.2
DIF:
PTS:
PTS:
PTS:
OBJ:
DIF:
DIF:
DIF:
OBJ: 17-3.4
OBJ: 18-1.1
OBJ: 18-2.1
A
Solution
PTS: 1
3. ANS: B
Given
Q = 2.67 C
t = 2.00 s
Solution
PTS: 1
4. ANS: B
5. ANS: C
Given
V = 120 V
R = 240 
Solution
PTS:
6. ANS:
7. ANS:
8. ANS:
1
A
C
A
IIIA
1
1
1
17-3.3
I
I
II
9. ANS: A
10. ANS: B
Given
R1 = 3.0 
R2 = 6.0 
R3 = 12 
PTS: 1
DIF: II
OBJ: 18-2.2
Solution
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
PTS: 1
DIF: IIIA
OBJ:
ANS: D
PTS: 1
DIF:
KEY: resistance | symbol
BLM:
ANS: B
PTS: 1
DIF:
KEY: resistor | series
BLM:
ANS: A
PTS: 1
DIF:
KEY: parallel | circuit | lamp
BLM:
ANS: A
PTS: 1
DIF:
KEY: resistance | series
BLM:
ANS: C
PTS: 1
DIF:
KEY: parallel | bulb | circuit
BLM:
ANS: D
PTS: 1
DIF:
KEY: parallel | circuit
BLM:
ANS: C
PTS: 1
DIF:
KEY: voltage | wire | parallel
BLM:
ANS: A
PTS: 1
DIF:
KEY: thick | series | voltage
BLM:
ANS: C
PTS: 1
DIF:
KEY: flow | charge
BLM:
ANS: E
PTS: 1
DIF:
KEY: voltage
BLM: comprehension
ANS: D
PTS: 1
DIF:
KEY: resistance | length
BLM:
ANS: B
Given
R1 = 8.0 
R2 = 2.0 
R3 = 10.0 
R4 = 5.0 

Solution
18-2.2
L1
OBJ:
knowledge
L2
OBJ:
comprehension
L2
OBJ:
comprehension
L2
OBJ:
comprehension
L2
OBJ:
application
L2
OBJ:
comprehension
L2
OBJ:
analysis
L2
OBJ:
analysis
L2
OBJ:
comprehension
L2
OBJ:
35.5 Schematic Diagrams
35.3 Series Circuits
35.4 Parallel Circuits
35.3 Series Circuits
35.4 Parallel Circuits
35.4 Parallel Circuits
35.4 Parallel Circuits
35.3 Series Circuits
34.1 Flow of Charge
34.3 Voltage Sources
L2
OBJ: 34.4 Electric Resistance
comprehension
R1,2 = R1 + R2 = 8.0  + 2.0  = 10.0 
Req = R1,2,3 + R4 = 5.00  + 5.0  = 10.0 
PTS: 1
DIF: IIIA
OBJ: 18-3.1
SHORT ANSWER
23. ANS:
potential energy associated with a charge due to the position of the charge in an electric field. It also can be
described as the amount of work done by an external agent to place a charge at a given location in an electric
field
PTS: 1
DIF: I
OBJ: 17-1.1
24. ANS:
Chemical reactions are the source of the energy in a battery.
PTS: 1
DIF: I
OBJ: 17-1.3
25. ANS:
Resistance is the opposition to electric current by a material or device.
PTS: 1
DIF: I
OBJ: 17-3.3
26. ANS:
Schematics should show symbols for the named circuit elements. The arrangement of the elements in either
series or parallel is not important.
PTS: 1
DIF: I
OBJ: 18-1.1
27. ANS:
There is no continuous path for current because the switch is open.
PTS: 1
DIF: II
OBJ: 18-1.2
28. ANS:
The lamp will go out, or the lamp will get dimmer. The resistance through the switch is lower than the
filament of the lamp.
PTS: 1
DIF: II
OBJ: 18-1.2
PROBLEM
29. ANS:
1.7  10 A
Given
Q 9.6 C
t 5.5  10
s
Solution
PTS: 1
30. ANS:
27.9 s
DIF: IIIA
OBJ: 17-3.1
DIF: IIIB
OBJ: 17-3.1
DIF: IIIA
OBJ: 17-3.3
Given
 1.48 A
Q 41.34 C
Solution
PTS: 1
31. ANS:
0.639 A
Given
R 227 
V 145 V
Solution
PTS: 1
32. ANS:
0.25 

Given
V 3.6 V
I
14.3 A
Solution
PTS: 1
33. ANS:
17 V
DIF: IIIA
OBJ: 17-3.3
Given
R 1.4 k 1.4  10 
I 0.012 A
Solution
PTS: 1
34. ANS:
7.1  10 V
DIF: IIIA
OBJ: 17-3.3
DIF: IIIA
OBJ: 17-3.3
Given
R 4.7  10 
I 1.52  10 A
Solution
PTS: 1
35. ANS:
49 
Given
R1 17 
R2 23 
R3 9 
Solution
For resistors in series,
Req
R1 + R2 + R3
PTS: 1
17  + 23  + 9 
DIF: I
49 
OBJ: 18-2.1
36. ANS:
71 
Given
I1 0.12 A
R1 5.1 
Vbatt 9.1 V
Solution
For a series circuit,
I1 I2 I 0.12 A
V1 R1I (5.1 )(0.12 A) 0.61 V
V2 Vbatt – V1 9.1 V – 0.61 V 8.5 V
PTS: 1
37. ANS:
4.93 
DIF: IIIB
OBJ: 18-2.1
Given
R1 11 
R2 15 
R3 22 
Solution
For resistors in parallel,
PTS: 1
38. ANS:
6A
DIF: IIIA
PTS: 1
DIF: L2
KEY: current | parallel | potential
39. ANS:
5.2 
Given
OBJ: 18-2.2
OBJ: 35.4 Parallel Circuits
BLM: application
R1
R2
R3
R4
2.0 
6.0 
10.0 
4.0 
Solution
R2,3 R2 + R3
6.0  + 10.0 
PTS: 1
40. ANS:
0.80 A
16.0 
DIF: IIIB
OBJ: 18-3.1
Given
R1 2.0 
R2 20.0 
R3 10.0 
R4 10.0 
Vbatt 12 V
I3 I4
Solution
R
V
2.0  + 4.00 
R +R
V
PTS: 1
(R
I )
6.0 
(4.00 )(2.0 A)
DIF: IIIB
8.0 V
OBJ: 18-3.2