1. 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
2. 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
3. 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. 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
4. A battery with an emf of 6.3 V is connected in series with a resistor of 2.0 ohms. What is the total power delivered by the battery to the circuit?
A) 22.0 W B) 20.0 W C) 12.6 W D) 25.2 W
5. A battery with an emf of 6.3 V is connected across the ends of an external resistor of 2 ohms. What is the current through the resistor?
A) 12.6 A B) 6.3 A C) 3.15 A D) 5.3 A
6. Three resistors having values of 4.0, 6.0 and 8.0 ohms, are connected in series. What is their equivalent resistance?
A) 18.0 ohms B) 8.0 ohms C) 6.0ohms D) 1.8 ohms
7. Three resistors having values of 4.0, 6.0 and 10.0 ohms, are connected in parallel. What is their equivalent resistance?
A) 20.0 ohms B) 7.3 ohms C) 6.0 ohms D) 1.9 ohms
8. Three resistors connected in parallel have individual values of 4.0, 6.0 and 10.0 ohms, respectively. If this circuit is connected to a 12.0 V battery what is the current in the 10 ohm resistor?
A) 0.55 A B) 5.2 A C) 1.2 A D) 2.0 A
9. Three resistors connected in parallel have individual values of 4.0, 6.0 and 10.0 ohms, respectively. If this combination is connected in series with a 12.0 V battery and a 2.0 ohm resistor, what is the current in the 10 ohm resistor?
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A) 0.59 A
B) 1.0 A
C) 11.2 A
D) 16.0 A
10. Consider the circuit shown in the figure. What power is dissipated by the entire circuit?
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A) 14 W
B) 28 W
C) 56 W
D) 112 W
11. 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
12. A series RC circuit has a time constant 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
13. A voltage source of 10 V is connected to a series 2 C circuit where R = 2 x 106 W and C = 3µF. Find the 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
14. In the circuit segment shown if I = 20 mA and Q = 50 µC. What is the potential difference, VA - VB?
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A) -40 V
B) +40 V
C) +20 V
D) -20 V
15. 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
16. If E = 24 V, at what rate is thermal energy generated in the 5 W resistor?
A) 13 W
B) 3.2 W
C) 23 W
D) 39 W
17. 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
18. 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?
A) 8 W B) 16 W C) 24 W D) 32 W
19. Four 1.5 volt AA batteries in series are used to 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
20. What is the maximum number of 100 Watt lightbulbs 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
21. An electric heater draws 1300 W, a toaster draws 1000 W, and an electric oven draws 1540 W. If all three of these appliances are operating in parallel on a 120 V circuit, what is the total current draw?
A) 23.4 A B) 31.7 A C) 39.9 A D) 47.7 A
22. How much power is being given off by one of the 10 ohm resistors?
A) 24.0 W
B) 9.6 W
C) 16.0 W
D) 6.4 W
23. What is the current flowing through the 2 ohm resistor?
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A) 2 A
B) 3 A
C) 4 A
D) 6 A
24. What is the current flowing through the 8 ohm resistor in the previous question?
A) 1 A B) 2 A C) 3 A D) 6 A
25. What is the equivalent resistance for these resistors?
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A) 2.3 ohms
B) 5.2 ohms
C) 13 ohms
D) 22 ohms
26. What is the equivalent resistance for these resistors?
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A) 1.33 ohms
B) 2.25 ohms
C) 3.0 ohms
D) 7.5 ohms
27. What is the potential difference between point a and b?
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A) 6 V
B) 8 V
C) 12 V
D) 24 V
28. How much current is flowing in one of the 10 ohm resistors?
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A) 0.8 A
B) 2.0 A
C) 1.6 A
D) 2.4 A
29. Consider the wheatstone bridge circuit. R3 = 4W and the ratio R2/R4 = 3 and the galvanometer reads zero current. If the current in R3 = 0.50 A, what is the current in R1?
0.17 A
0.50 A
1.5 A
0.75 A
30. What is the current through the 4 ohm resistor?
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A) 1.0 A
B) 0.5 A
C) 1.5 A
D) 2.0 A
31. What is the current through the 8 ohm resistor?
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A) 1.0 A
B) 0.5 A
C) 1.5 A
D) 2.0 A
32. Consider the wheatstone bridge circuit. R3 = 4W and the ratio R2/R4 = 3 and the galvanometer reads zero current. If the current in R3 is 0.50 A, what is the current in R4?
A) 0.17 A
B) 0.50 A
C) 1.5 A
D) 0.75 A
33. Consider the wheatstone bridge circuit. R3 = 4W and the ratio R2/R4 = 3. The galvanometer reads zero current. What is R1?
A) 0.75 ohms
B) 1.33 ohms
C) 12 ohms
D) 15 ohms
34. Consider the wheatstone bridge circuit. R3 = 4W and the ratio R2/R4 = 3 and the galvanometer reads zero current. The potential difference across R4 is 3 V. What is the potential difference across R2?
A) 1 V
B) 2 V
C) 3 V
D) 9 V
35. 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
36. 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,
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
37. 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
38. 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
39. 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
40. Which resistor is in series with resistor R?
A) R1
B) R2
C) R3
D) R4
41. Which two resistors are in parallel with each other in the previous question?
A) R and R4 B) R2 and R3 C) R2 and R4 D) R and R1
42. 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, tau, 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 tau 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
43. A 1000 V battery, a 3000 ohm resistor and a 0.5 microfarad 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 in the previous question?
A) 0.39 A B) 0.33 A C) 0.84 A D) 2000 A
44. in the circuit of question # 42, The time constant for such a circuit, designated by the Greek letter, tau, 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 tau for this circuit?
A) 6.0 x 109 s B) 1.67 x 10-10 s C) 1.67 x 10-7 s D) 1.5 x 10-3 s
45. Two resistors of values 6 and 12 ohms are connected in parallel. This combination in turn is hooked in series with a 3 ohm 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
46. Which of the following devices is designed to measure an approximate value for the resistance of a conductor?
A) ammeter/voltmeter combination
B) voltmeter
C) thermocouple
D) ammeter
47. Three resistors, with values of 3, 6 and 12 ohms, respectively, are connected in series. What is the overall resistance of this combination?
A) 0.58 ohms B) 1.7 ohms C) 7.0 ohms D) 21.0 ohms
48. Three resistors, with values of 3, 6 and 12 ohms, respectively, are connected in parallel. What is the overall resistance of this combination?
A) 0.58 ohms B) 1.7 ohms C) 7.0 ohms D) 21.0 ohms
49. Which of the following devices is designed to measure the resistance of a conductor more accurately?
A) ammeter/voltmeter combination B) voltmeter
C) Wheatstone bridge D) ammeter
50. Two resistors of values 6 and 12 ohms are connected in parallel. This combination in turn is hooked in series with a 4 ohm resistor. What is the overall resistance of this combination?
A) 0.5 ohms B) 2.0 ohms C) 8.0 ohms D) 22.0 ohms
51. Two resistors of values 6 and 12 ohms are connected in parallel. This combination in turn is hooked in series with a 2 ohm resistor and a 24 V battery. What is the current in the 2 ohm resistor?
A) 2.0 A B) 4.0 A C) 6.0 A D) 12.0 A
52. 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
53. 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
54. 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
55. 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
56. 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
57. 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
58. A circuit contains 3 V battery, a 2 ohm resistor, a 0.3 microfarad capacitor, an ammeter, and a switch all in series. What will be the current reading 10 min after the switch is closed?
A) Zero
B) 0.75 A
C) 1.5 A
D) 107 A
59. A circuit contains a 3 V battery, a 2 ohm resistor, a 0.3 microfarad 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
60. 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 of the above are valid
D) None of the above choices are valid
ANSWER KEY
1- zero A, 10 V
2- 21 A
3- 5 A, zero V
4- 20.0 W
5- 3.15A
6- 18.0 ohms
7- 1.9 ohms
8- 1.2 A
9- 0.59 A
10- 56 W
11- 1.5 mC, left plate is positive
12- 0.43 C
13- 18 s
14- -20 V
15- 1.6 W
16- 13 W
17- 0.20 A
18- 16 W
19- 2.2 hours
20- 23
21- 31.7 A
22- 6.4 W
23- 4 A
24- 1 A
25- 5.2 ohms
26- 2.25 ohms
27- 12 V
28- 0.8 A
29- 0.17 A
30- 1.0 A
31- 1.5 A
32- 0.50 A
33- 12 ohms
34- 3 V
35- none of the above
36- the voltage across R equals the voltage across R1
37- I1 + I2 + I3 = 0
38- the current through R equals the current through R1
39- the voltage across a charged capacitor
40- R4
41- R2 and R3
42- 0.12 A
43- 0.33 A
44- 1.5 x 10-3 s
45- 2.0 A
46- ammeter/voltmeter combination
47- 21.0 ohms
48- 1.7 ohms
49- Wheatstone bridge
50- 8.0 ohms
51- 4.0 A
52- Rt = (1/R1 + 1/R2 + 1/R3)-1
53- Rt = R1 + R2 + R3
54- Vt = V1 = V2 = V3
55- Vt = V1 + V2 + V3
56- It = I1 = I2 = I3
57- It = I1 + I2 + I3
58- zero
59- zero
60- convert some other form of energy into electrical
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