1. Electric Currents and Circuits Review

2. How much work is done to transfer 0.18 C of charge through a potential difference of 12 volts? Ans. 2.16 J

3. A spark will jump through dry air when the electric field is larger than 1000 volts/m. If two parallel plates have a potential difference of 5000 V, what is the minimum distance between them to prevent discharge? Ans. 5 m

4. A certain X-ray tube uses 125,000 volts to accelerate electrons to produce X-rays. What is the kinetic energy of the electrons just before they strike the tungsten metal? Ans. 2 x 10 -14 J

5. Which of the following arrangements of three identical resistors will produce the lowest value of current through the battery? Ans. A

6. Which of the following arrangements of three identical resistors will produce the largest value of current through the battery? Ans. C

7. Which graph could represent I vs. V in a simple circuit? Ans. C

8. What is the current in the circuit? V A1A1 10  A2A2 60 V Ans. 3 A

9. An electric heater draws 15 A when connected to a 120 V source. It is operated for 5 hours every day. At a cost of $0.08 per kWh, how much does it cost to operate the heater for 30 days? (1kWh = 3.6  10 6 J) Ans. $21.60

10. What is the voltage drop across the left resistor? V A1A1 10  A2A2 60 V Ans. 30 V

11. If R 3 is 150 , what is the current through it? V A 1 A 80 V R1R1 R2R2 R3R3 240  Ans. 0.53 A

12. What is R 1 ? V A 1 A 80 V R1R1 R2R2 R3R3 240  Ans. 80 

13. While stringing a line of Christmas tree lights you notice that one of the bulbs has burned out. The rest of the bulbs remain lit. The bulbs must be wired in Series Parallel Cannot be determined Ans. parallel

14. What is the power dissipated by R 2 ? V A 1 A 80 V R1R1 R2R2 R3R3 240  Ans. 26.7 W

15. What is the current through the 5  resistor? 100 V 10  5  15  Ans. 3.33 A

16. What is the total resistance of this circuit? 100 V 10  5  15  Ans. 30 

17. What is the voltage V 2 ? 60 V 10  5  15  Ans. 60 V

18. What is the voltage drop V 3 ? 100 V 10  5  15  Ans. 50 V

19. What is the total resistance of this circuit? 60 V 10  5  15  Ans. 2.73 

20. What is the current in the rightmost branch? 60 V 10  5  15  Ans. 4 A

21. Which diagram shows a possible flow of current in part of a circuit? Ans. A

22. What is the current through the battery in this circuit? 60 V 10  5  15  Ans. 22 A

23. An electrical heater raises the temperature of a bucket of water. If 6000 J of energy is absorbed by the water from the heater in 30 s, what is the minimum power rating of the heater? Ans. 200 W

24. Which circuit shows the correct setup for the ammeter and voltmeter in a parallel circuit? Ans. B