Chapter 17 (DC Current)
1. The two ends of a 3 W resistor are connected to a 9 V battery. What is the current through the resistor?
a. 27 A
b. 6.3 A
c. 3.0 A
d. 0.33 A
2. The two ends of a 3 W resistor are connected to a 9 V battery. What is the total power delivered by the battery to the circuit?
a. 3.0 W
b. 27.0 W
c. 1/3 W
d. 1/9 W
3. Three 8.0 W resistors are connected in series. What is their equivalent resistance?
a. 24.0 W
b. 8.0 W
c. 0.38 W
d. 0.13 W
4. Three 8.0 W resistors are connected in parallel. What is their equivalent resistance?
a. 0.054 W
b. 0.13 W
c. 0.38 W
d. 2.7 W
5. Three 4.0 W resistors are connected in parallel to a 12.0 V battery. What is the current in any one of the resistors?
a. 16 A
b. 9.0 A
c. 3.0 A
d. 48 A
6. Three resistors connected in parallel have individual values of 4.0, 6.0 and 10.0 W, respectively. If this combination is connected in series with a 12.0 V battery and a 2.0 W resistor, what is the current in the 10 W resistor?
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a. 0.59 A b. 1.0 A c. 11.2 A d. 16.0 A
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7. A 10 V emf battery is connected in series with the following: a 2 µF capacitor, a 2 W 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?
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a. zero A, 10 V b. zero A, zero V c. 5 A, zero V d. 5 A, 10 V
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8. A 10 V emf battery is connected in series with the following: a 2 microFarad capacitor, a 2 ohm 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?
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a. zero A, 10 V b. zero A, zero V c. 5 A, zero V d. 5 A, 10 V
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9. The following three appliances are connected to a 120 volt house circuit: i) toaster, 1200 W, ii) coffee pot, 750 W. and iii) microwave, 600 W. If all were operated at the same time what total current would they draw?
a. 3 A
b. 5 A
c. 10 A
d. 21 A
10. The basic function of an electromotive force in a circuit is to do which of the following?
a. convert electrical energy into some other form
b. convert some other form of energy into electrical
c. Both choices (a) and (b) are valid
d. None of the above choices are valid
11. A circuit contains 3 V battery, a 2 W resistor, a 0.3 µF capacitor, an ammeter, and a switch all in series. What will be the current reading 10 min after the switch is closed?
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a. zero b. 0.75 A c. 1.5 A d. 107 A
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12. A circuit contains a 3 V battery, a 2 Wresistor, a 0.3 µF capacitor, an ammeter, and a switch in series. The sum of all the potential differences taken for all the components going around the loop is which of the following?
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a. zero b. 3.0 V c. ‑3.0 V d. 6.0 V
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13. Three resistors connected in parallel each carry currents labeled I1, I2 and I3. Which of the following expresses the value of the total current It in the combined system?
a. It = I1 + I2 + I3
b. It = (1/I1 + 1/I2 + 1/I3)
c. It = I1 = I2 = I3
d. It = (1/I1 + 1/I2 + 1/I3)-1
14. Three resistors connected in series each carry currents labeled I1, I2 and I3. Which of the following expresses the value of the total current It in the system made up of the three resistors in series?
a. It = I1 + I2 + I3
b. It = (1/I1 + 1/I2 + 1/I3)
c. It = I1 = I2 = I3
d. It = (1/I1 + 1/I2 + 1/I3)-1
15. Three resistors connected in series have individual voltages labeled V1, V2 and V3, respectively. Which of the following expresses the value of the total voltage taken over the three resistors together?
a. Vt = V1 + V2 + V3
b. Vt = (1/V1 + 1/V2 + 1/V3)
c. Vt = V1 = V2 = V3
d. Vt = (1/V1 + 1/V2 + 1/V3)-1
16. Three resistors connected in parallel have the individual voltages labeled V1, V2 and V3, respectively. Which of the following expresses the total voltage across the three resistors when connected in this manner?
a. Vt = V1 + V2 + V3
b. Vt = (1/V1 + 1/V2 + 1/V3)
c. Vt = V1 = V2 = V3
d. Vt = (1/V1 + 1/V2 + 1/V3)-1
17. Three resistors with values of R1, R2 and R3, respectively, are connected in series. Which of the following expresses the total resistance, Rt, of the three resistors?
a. Rt = R1 + R2 + R3
b. Rt = (1/R1 + 1/R2 + 1/R3)
c. Rt = R1 = R2 = R3
d. Rt = (1/R1 + 1/R2 + 1/R3)-1
18. Three resistors with values R1, R2 and R3, respectively, are connected in parallel. Which of the following expresses the total resistance, Rt, of the three resistors when connected in parallel?
a. Rt = R1 + R2 + R3
b. Rt = (1/R1 + 1/R2 + 1/R3)
c. Rt = R1 = R2 = R3
d. Rt = (1/R1 + 1/R2 + 1/R3)-1
19. Three resistors, with values of 3, 6 and 12 W, respectively, are connected in series. What is the overall resistance of this combination?
a. 0.58 W
b. 1.7 W
c. 7.0 W
d. 21.0 W
20. Three resistors, with values of 3, 6 and 12 W, respectively, are connected in parallel. What is the overall resistance of this combination?
a. 0.58 W
b. 1.7 W
c. 7.0 W
d. 21.0 W
21. Two resistors of values 6 and 12 W are connected in parallel. This combination in turn is hooked in series with a 4 Wresistor. What is the overall resistance of this combination?
a. 0.5 W
b. 2.0 W
c. 8.0 W
d. 22.0 W
22. Two resistors of values 6 and 12 W are connected in parallel. This combination in turn is hooked in series with a 2 W resistor and a 24 V battery. What is the current in the 2 W resistor?
a. 2.0 A
b. 4.0 A
c. 6.0 A
d. 12.0 A
23. Two resistors of values 6 and 12 W are connected in parallel. This combination in turn is hooked in series with a 3 W resistor and a 24 V battery. What is the current in the 6 ohm resistor?
a. 2.0 A
b. 3.0 A
c. 6.0 A
d. 12.0 A
24. A 1000 V battery, a 3000 W resistor and a 0.5 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?
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a. 0.39 A b. 0.33 A c. 0.84 A d. 2000 A
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25. A 1000 V battery, a 3000 W resistor and a 0.5 µF capacitor are connected in series with a switch. The time constant for such a circuit, designated by the Greek letter, t, 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 t for this circuit?
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a. 6.0 ´ 109 s b. 1.67 ´ 10-10 s c. 1.67 ´ 10‑7 s d. 1.5 ´ 10‑3 s
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26. A 1000 V battery, a 3000 ohm resistor and a 0.5 microFarad capacitor are connected in series with a switch. The time constant for such a circuit, designated by the Greek letter, t, is defined as the time that the capacitor takes to charge to 63% of its capacity after the switch is closed. What is the current in the circuit at a time interval of t seconds after the switch has been closed?
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a. 0.14 A b. 0.21 A c. 0.12 A d. 0.32 A
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27. Which voltage is not caused by a source of emf?
a. the voltage across a charged capacitor
b. the voltage across two copper‑iron junctions at different temperatures
c. the voltage across the terminals of a dry cell battery
d. the voltage from an electric generator
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28. Which resistor is in series with resistor R?
a. R1 b. R2 c. R3 d. R4
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29. Which two resistors are in parallel with each other?
a. R and R4 b. R2 and R3 c. R2 and R4 d. R and R1
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30. Three resistors, each with resistance R1, are in series in a circuit. They are replaced by
one equivalent resistor, R. Comparing this resistor to the first resistor of the previous circuit.
a. the current through R equals the current through R1
b. the voltage across R equals the voltage across R1
c. the power given off by R equals the power given off by R1
d. R is smaller than R1
31. Three resistors, each with resistance R1, are in parallel in a circuit. They are replaced by one equivalent resistor, R. Comparing this resistor to the first resistor of the previous circuit. Which of the following statements is true?
a. the current through R equals the current through R1
b. the voltage across R equals the voltage across R1
c. the power given off by R equals the power given off by R1
d. R is bigger than R1
32. What is Kirchhoff’s 1st equation for this junction?
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a. I1 = I2 + I3 b. I2 = I1+ I2 c. I3 = I1 + I2 d. I1 + I2 + I3 = 0
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33. If a certain capacitor is charged to 10 V and then, at t = 0, allowed to discharge through a certain resistor. There will be a certain time before the voltage across the capacitor reaches 5 V. This time can be decreased for this circuit by increasing:
a. the size of the capacitor.
b. the size of the resistor.
c. the size of the time constant.
d. none of the above
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34. What is the current through the 4 W resistor? a. 1.0 A b. 0.5 c. 1.5 A d. 2.0 A
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35. What is the current through the 8 W resistor?
a. 1.0 A b. 0 5 A c. 1.5 A d. 2.0 A
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36. What is the potential difference between points a and b? a. 6V b. 8 V c. 12 V d. 24 V |
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37. What is the current flowing through the 2 W resistor? a. 2 A b. 3 A c. 4 A d. 6 A
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38. What is the current flowing through the 8 W resistor? a. 1 A b. 2 A c. 3 A d. 6V
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39. What is the equivalent resistance for these resistors? a. 2.3 W b. 2.25 W c. 3.0 W d. 22 W
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40. What is the equivalent resistance for these resistors? resistors?
a. 1.33 W b. 2.25 W c. 3.0 W d. 7.5 W
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41. How much current is flowing in one of the 10 W resistors?
a. 0.8 A b. 2.0 A c. 1.6 A d. 2.4 A
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42. How much power is being given off by one of the 10 W resistors?
a. 24.0 W b. 9.6 W c. 16.0 W d. 6.4 W
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43. 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 W?
a. 1.1 hours
b. 2.2 hours
c. 4.1 hours
d. 13 hours
44. What is the maximum number of 100 Watt light bulbs you can connect in parallel in a 120 V home circuit without tripping the 20 A circuit breaker?
a. 11
b. 17
c. 23
d. 29
45. An hair dryer draws 1200 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 draw?
a. 19.4 A
b. 20.8 A
c. 25.4 A
d. 36.7 A
46. In a circuit, a current of 1.0 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 W and the current through it is 0.2 A. What is the value of the other resistor?
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a. 8 W b. 16 W c. 24 W d. 32 W
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47. If E = 20 V, at what rate is thermal energy being generated in the 20 W resistor?
a. 6.5 W b. 1.6 W c. 15 W d. 26 W
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48. If E = 24 V, at what rate is thermal energy generated in the 20 W resistor?
a. 13 W b. 3.2 W c. 23 W d. 39 W |
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49. If E = 9.0 V, what is the current in the 15 W resistor?
a. 0.20 A b. 0.30 A c. 0 10 A d. 0.26 A
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50. In the circuit segment shown if I = 2 mA and Q = 50 µC. What is the potential difference, VA – VB?
a. ‑40 V b. +40 V c. +20 V d. ‑20 V
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51. If I = 2.0 mA and the potential difference, VA – VB = +30 V in the circuit segment shown, determine the charge and polarity of the capacitor.
a. 1.5 mC, left plate is positive b. 1.5 mC, right plate is positive c. 0.50 mC, left plate is positive d. 0.50 mC, right plate is positive
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52. A series RC circuit has a time content of 1.0 s. The battery has a voltage of 50 V and the maximum current just after closing the switch is 500 mA. The capacitor is initially uncharged. What is the charge on the capacitor 2.0 s after the switch is closed?
a. 0.43 C b. 0 66 C c. 0.86 C d. 0.99 C |
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53. A voltage source of 10 V is connected to a series RC circuit where R = 2 ´ 106 W, and C = 3 µF. Find the amount of time required for the current in the circuit to decay to 5% of its original value.
a. 3 s
b. 6 s
c. 9 s
d. 18 s
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54. Consider the circuit shown in the figure. What power is dissipated by the entire circuit?
a. 14 W b. 28 W c. 56 W d. 112 W
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Chapter 17 - Answers
# Ans Difficulty # Ans Difficulty
1. C 1 29. B 2
2. B 1 30. A 1
3. A 1 31. B 1
4. D 1 32. D 1
5. C 2 33. D 2
6. A 2 34. A 3
7. C 2 35. C 3
8. A 2 36. C 3
9. D 2 37. C 2
10. B 1 38. A 2
11. A 2 39. B 2
12. A 2 40. B 2
13. A 1 41. A 2
14. C 2 42. D 2
15. A 1 43. B 2
16. C 1 44. C 2
17. A 1 45. B 2
18. D 1 46. B 2
19. D 1 47. B 3
20. B 2 48. A 3
21. C 1 49. A 2
22. B 1 50. D 3
23. A 2 51. A 3
24. B 2 52. A 3
25. D 3 53. D 3
26. C 3 54. C 2
27. A 1
28. D 2