1

DC Circuits

____ 1. The two ends of a 3.0- resistor are connected to a 9.0-V battery. What is the current through the resistor?

a.27 A c.3.0 A

b.6.3 A d.0.33 A

____ 2. The two ends of a 3.0- resistor are connected to a 9.0-V battery. What is the total power delivered by the

battery to the circuit?

a.3.0 W c.0.33 W

b.27 W d.0.11 W

____ 3. Three 8.0- resistors are connected in series. What is their equivalent resistance?

a.24.0 c.0.38

戮 㠮〠 d.0.13

彟彟 㐮4 周牥攠牥獩獴潲猠捯湮散瑥搠楮敲楥猠敡捨慲特畲牥湴猠污扥汥搠 I

1

, I

2

and I

3

. Which of the following expresses

the value of the total current I

T

in the system made up of the three resistors in series?

a.I

T

= I

1

+ I

2

+ I

3

c.I

T

= I

1

= I

2

= I

3

b.I

T

= (1/I

1

+ 1/I

2

+ 1/I

3

) d.I

T

= (1/I

1

+ 1/I

2

+ 1/I

3

)

1

彟彟 㔮5 周牥攠牥獩獴潲猠捯湮散瑥搠楮敲楥猠桡癥湤楶楤畡氠癯汴慧敳慢敬敤T V

1

, V

2

and V

3

, respectively. Which of

the following expresses the value of the total voltage V

T

taken over the three resistors together?

a.V

T

= V

1

+ V

2

+ V

3

c.

V

T

=

V

1

=

V

2

=

V

3

b.V

T

= (1/V

1

+ 1/V

2

+ 1/V

3

) d.

V

T

= (1/

V

1

+ 1/

V

2

+ 1/V

3

)

1

____ 6. Three resistors with values of R

1

, R

2

and R

3

, respectively, are connected in series. Which of the following

expresses the total resistance, R

T

, of the three resistors?

a.R

T

= R

1

+ R

2

+ R

3

c.R

T

= R

1

= R

2

= R

3

b.R

T

= (1/R

1

+ 1/R

2

+ 1/R

3

) d.R

T

= (1/R

1

+ 1/R

2

+ 1/R

3

)

1

____ 7. Three resistors, with values of 2.0, 4.0 and 8.0 , respectively, are connected in series. What is the overall

resistance of this combination?

a.0.58 c.7.0

b.1.1 d.14.0

____ 8. Three resistors, each with resistance R

1

, are in series in a circuit. They are replaced by one equivalent resistor,

R. Comparing this resistor to the first resistor of the initial circuit, which of the following is true?

a.The current through R equals the current

through R

1

.

c.The power given off by R equals the

power given off by R

1

.

b.The voltage across R equals the voltage

across R

1

.

d.R is less than R

1

.

____ 9. Three resistors connected in parallel each carry currents labeled I

1

, I

2

and I

3

. Which of the following expresses

the value of the total current I

T

in the combined system?

a.I

T

= I

1

+ I

2

+ I

3

c.I

T

= I

1

= I

2

= I

3

b.I

T

= (1/I

1

+ 1/I

2

+ 1/I

3

) d.I

T

= (1/I

1

+ 1/I

2

+ 1/I

3

)

1

2

____ 10. Three resistors connected in parallel have the individual voltages labeled V

1

, V

2

and V

3

, respectively.

Which of the following expresses the total voltage V

T

across the three resistors when connected in this

manner?

a.V

T

= V

1

+ V

2

+ V

3

c.

V

T

=

V

1

=

V

2

=

V

3

b.V

T

= (1/V

1

+ 1/V

2

+ 1/V

3

) d.

V

T

= (1/

V

1

+ 1/

V

2

+ 1/V

3

)

1

____ 11. Three resistors with values R

1

, R

2

and R

3

, respectively, are connected in parallel. Which of the following

expresses the total resistance, R

T

, of the three resistors when connected in parallel?

a.R

T

= R

1

+ R

2

+ R

3

c.R

T

= R

1

= R

2

= R

3

b.R

T

= (1/R

1

+ 1/R

2

+ 1/R

3

) d.R

T

= (1/R

1

+ 1/R

2

+ 1/R

3

)

1

____ 12. Three resistors, each with resistance R

1

, are in parallel in a circuit. They are replaced by one equivalent

resistor, R. Compare this resistor to the first resistor of the initial circuit. Which of the following statements is

true?

a.The current through R equals the current

through R

1

.

c.The power given off by R equals the

power given off by R

1

.

b.The voltage across R equals the voltage

across R

1

.

d.R is greater than R

1

.

____ 13. If R

1

< R

2

< R

3

,

and if these resistors are connected in parallel in a circuit, which one has the highest current?

a.R

1

c.R

3

b.R

2

d.All have the same current.

____ 14. What is Kirchhoff’s 1st equation for this junction?

a.I

1

= I

2

+ I

3

c.I

3

= I

1

+ I

2

b.I

2

= I

1

+ I

2

d.I

1

+ I

2

+ I

3

= 0

____ 15. If I

1

goes to the right through R

1

, I

2

goes to the right through R

2

, and I

3

goes to the right through R

3

, what is

the resulting equation resulting from applying Kirchhoff’s junction rule at point b?

a.I

1

+ I

2

+ I

3

= 0 c.I

1

– I

2

+ I

3

= 0

b.I

1

+ I

2

– I

3

= 0 d.I

1

– I

2

– I

3

= 0

3

____ 16. The internal resistances of an ideal voltmeter and an ideal ammeter are respectively (ideal meaning the

behavior of the system is not changed when using the meter):

a.zero and zero.c.zero and infinite.

b.infinite and infinite.d.infinite and zero.

____ 17. When a 24.0- resistor is connected across a 12.0-V battery, a current of 482 mA flows. What is the internal

resistance of the battery?

a.0.02 c.25.0

戮 〮㤠 d.49.8

彟彟 ㄸ⸠ 坨敮′㐮〭 resistor is connected across a 12.0-V battery, a current of 482 mA flows. What is the power

output delivered by the emf of the battery?

a.0.21 W c.5.78 W

b.5.57 W d.6.00 W

____ 19. Which resistor is in series with resistor R?

a.R

1

c.R

3

b.R

2

d.R

4

____ 20. If R

1

< R

2

< R

3

,

and if these resistors are connected in series in a circuit, which one dissipates the greatest

power?

a.R

1

c.R

3

b.R

2

d.All are equal in power dissipation.

____ 21. Resistors of values 8.0 , 12.0 , and 24.0 are connected in series across a battery with a small internal

resistance. Which resistor dissipates the greatest power?

a.the 8.0- resistor c.the 24.0-

敳楳瑯

戮 瑨攠ㄲ⸰t resistor d.The answer depends on the internal

resistance of the battery.

____ 22. Three 8.0- resistors are connected in parallel. What is their equivalent resistance?

a.0.054 c.0.38

戮 〮ㄳ0 d.2.7

彟彟′㌮ 周牥攠㐮〭 resistors are connected in parallel to a 12.0-V battery. What is the current in any one of the

resistors?

a.16 A c.3.0 A

b.9.0 A d.48 A

____ 24. Three resistors, with values of 2.0, 4.0 and 8.0 , respectively, are connected in parallel. What is the overall

resistance of this combination?

a.0.58 c.7.0

戮 ㄮㄠ d.14.0

4

____ 25. Two resistors of values 6.0 and 12.0 are connected in parallel. This combination in turn is hooked in series

with a 4.0- resistor. What is the overall resistance of this combination?

a.0.50 c.8.0

b.2.0 d.22.0

____ 26. Two resistors of values 6.0 and 12.0 are connected in parallel. This combination in turn is hooked in series

with a 2.0- resistor and a 24-V battery. What is the current in the 2- resistor?

a.2.0 A c.6.0 A

b.4.0 A d.12 A

____ 27. Two resistors of values 6.0 and 12.0 are connected in parallel. This combination in turn is hooked in series

with a 4.0- resistor and a 24-V battery. What is the current in the 6- resistor?

a.2.0 A c.6.0 A

b.3.0 A d.12 A

____ 28. Which two resistors are in parallel with each other?

a.R and R

4

c.R

2

and R

4

b.R

2

and R

3

d.R and R

1

____ 29. Resistors of values 6.0, 4.0, 10.0 and 7.0 are combined as shown. What is the equivalent resistance for

this combination?

a.2.3 c.10.7

b.3.0 d.27

____ 30. What is the equivalent resistance for these 3.00- resistors?

a.1.33 c.3.00

戮 ㈮㈵2 d.7.50

5

____ 31. How much current is flowing in one of the 10- resistors?

a.0.8 A c.1.6 A

b.2.0 A d.2.4 A

____ 32. How much power is being dissipated by one of the 10- resistors?

a.24 W c.16 W

b.9.6 W d.6.4 W

____ 33. If = 9.0 V, what is the current in the 15- resistor?

a.0.20 A c.0 10 A

b.0.30 A d.0.26 A

____ 34. Consider the circuit shown in the figure. What power is dissipated by the entire circuit?

a.14 W c.52 W

b.28 W d.112 W

6

____ 35. If I

1

goes to the right through R

1

, I

2

goes to the right through R

2

, and I

3

goes to the right through R

3

, what is

the resulting equation resulting from applying Kirchhoff’s loop rule for a clockwise loop around the perimeter

of the circuit?

a.8.0 V + I

1

R

1

+ I

3

R

3

= 0 c.8.0 V – I

1

R

1

+ I

3

R

3

= 0

b.8.0 V + I

1

R

1

– I

3

R

3

= 0 d.–8.0 V + I

1

R

1

+ I

3

R

3

= 0

____ 36. What is the current flowing through the 2- resistor?

a.2 A c.4 A

b.3 A d.6 A

____ 37. What is the current flowing through the 4- resistor?

a.1 A c.3 A

b.2 A d.6 A

____ 38. Four 1.5-volt AA batteries in series power a transistor radio. If the batteries hold a total charge of 240 C, how

long will they last if the radio has a resistance of 200 ?

a.1.1 h c.4.1 h

b.2.2 h d.13 h

7

____ 39. In a circuit, a current of 2.0 A is drawn from a battery. The current then divides and passes through two

resistors in parallel. One of the resistors has a value of 64 and the current through it is 0.40 A. What is the

value of the other resistor?

a.8.0 c.24

b.16 d.32

____ 40. A 10-V-emf battery is connected in series with the following: a 2-µF capacitor, a 2- resistor, an ammeter,

and a switch, initially open; a voltmeter is connected in parallel across the capacitor. At the instant the switch

is closed, what are the current and capacitor voltage readings, respectively?

a.zero A, 10 V c.5 A, zero V

b.zero A, zero V d.5 A, 10 V

____ 41. A 10-V-emf battery is connected in series with the following: a 2-F capacitor, a 2- resistor, an ammeter,

and a switch, initially open; a voltmeter is connected in parallel across the capacitor. After the switch has been

closed for a relatively long period (several seconds, say), what are the current and capacitor voltage readings,

respectively?

a.zero A, 10 V c.5 A, zero V

b.zero A, zero V d.5 A, 10 V

____ 42. A circuit contains a 6.0-V battery, a 4.0- resistor, a 0.60-µF capacitor, an ammeter, and a switch all in series.

What will be the current reading immediately after the switch is closed?

a.zero c.1.5 A

b.0.75 A d.10 A

8

____ 43. A circuit contains a 6.0-V battery, a 4.0- resistor, a 0.60-µF capacitor, an ammeter, and a switch in series.

What will be the charge on the capacitor 10 min after the switch is closed?

a.zero c.3.6

C

戮 〮0

C d.㈮㐠

C

彟彟 㐴⸠ 䄠ㄠ〰〭嘠扡瑴敲礬″‰〰A resistor, and a 0.50-µF capacitor are connected in series with a switch. The

capacitor is initially uncharged. What is the value of the current the moment after the switch is closed?

a.0.39 A c.0.84 A

b.0.33 A d.2 000 A

____ 45. A 1 000-V battery, a 3 000- resistor and a 0.50-µF capacitor are connected in series with a switch. The time

constant for such a circuit, designated by the Greek letter, , is defined as the time required to charge the

capacitor to 63% of its capacity after the switch is closed. What is the value of for this circuit?

a.6.0 10

9

s c.1.7

‱

7

s

b.1.7 10

10

s d.1.5

‱

3

s

____ 46. The following three appliances are connected to a 120-V house circuit: i) toaster, 1 200 W, ii) coffee pot, 750

W, and iii) microwave, 800 W. If all were operated at the same time, what total current would they draw?

a.3.0 A c.10 A

b.5.0 A d.23 A

____ 47. What is the maximum number of 60-W light bulbs you can connect in parallel in a 120-V home circuit

without tripping the 30-A circuit breaker?

a.11 c.59

b.35 d.3 600

____ 48. A hair dryer draws 1 200 W, a curling iron draws 800 W, and an electric light fixture draws 500 W. If all

three of these appliances are operating in parallel on a 120-V circuit, what is the total current drawn?

a.19.4 A c.25.4 A

b.20.8 A d.36.7 A

ID: A

1

DC Circuits

Answer Section

MULTIPLE CHOICE

1. C

2. B

3. A

4. C

5. A

6. A

7. D

8. A

9. A

10. C

11. D

12. B

13. A

14. D

15. A

16. D

17. B

18. C

19. D

20. C

21. C

22. D

23. C

24. B

25. C

26. B

27. A

28. B

29. C

30. B

31. A

32. D

33. A

34. C

35. C

36. C

37. A

38. B

39. B

40. C

ID: A

2

41. A

42. C

43. C

44. B

45. D

46. D

47. C

48. B

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