Name: Exam 3--PHYS 102--S14 Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Which of these statements is always true? a. resistors in parallel have the same voltage b. the equivalent resistance of resistors in parallel is bigger than any one of the resistors c. the sum of the potentials for resistors in series is zero d. the current for resistors in parallel is the same 2. The terminal voltage of a battery is always than the ideal electromotive force because of. a. smaller, Ohm s law b. larger, large current c. smaller, internal resistance d. larger, 3. What is the equivalent resistance of this circuit? 5. For the previous circuit, what is the current through the 6 resistor? a. 3 A b. 12 A c. 2 A d. 1 A e. 0.5 A 6. An ohm is a unit of a. resistivity b. inductance c. potential difference d. resistance e. current 7. Consider this circuit. If one of the 2 resistors is removed, what happens to the voltage across the remaining resistor? a. 11 b. 1.6 c. 1 d. 4 4. For the previous problem, what is the voltage across the 2 resistor? a. 3 V b. 4 V c. 6 V d. 8 V e. 12 V a. it increases b. it is the same c. it decreases d. it depends on how quickly you remove the resistor 8. For the above circuit, what happens to the total current coming off of the battery if you remove one of the resistors? a. it increases b. it remains the same c. it decreases 1
9. Consider this circuit. What is the equivalent resistance? a. 10 b. 1.7 c. 7 d. 0.4 e. 1.2 10. Consider the circuit in the previous problem. For which resistor is the current greatest? a. R 1 b. R 2 c. R 3 d. R 5 13. The third prong in the electrical outlet provides protection from. a. very wet areas b. faulty devices c. too much current on a circuit d. your gossipy aunt 14. Consider a series RC circuit for which R = 2.0 M, C=5.0 µf, and =20 V. Find the charge on the capacitor 10 s after the switch is closed. a. 52 F b. 63 F c. 100 F d. 37 F e. 200 F 15. Which of the following equations for this circuit is correct? 11. Consider this circuit. Which of the following graphs represents the current versus time after the switch is closed and current is allowed to flow in the circuit. a. A b. B c. C d. D a. -6I 2 +10+4I 1 +14=0 b. -6+10+6I 2 =0 c. 14-4I 3 +6=0 d. 14-4I 1 +6I 3 =0 16. Consider the above circuit. What is magnitude and direction of I 2? 12. A 4.0 resistor, an 8.0 resistor, and a 12 resistor are connected in series with a 12 V battery. What is the current in the 8.0 resistor? a. 0.25 A b. 0.5 A c. 2.0 A d. 1.0 A a. 0 A b. 1.5 A to the left c. 0.67 A to the right d. 2.7 A to the right 2
17. If the switch S is closed, what happens to the current through R 1? 20. Which of these statements about a household circuit is true: I. The household circuit is a series circuit. II. All devices in a household circuit operate at the same current. III. As you add more devices to a household circuit, the total current increases. a. decreases b. stays the same c. increases d. not enough information 18. You turn on a light in your house. What happens to the potential across other applicances on the same circuit? a. the potential increases b. the potential decreases c. the potential stays the same IV. A ground fault circuit interrupt turns off if I in >I out for any particular device. a. II & III b. III c. III & IV d. I & IV 21. A capacitor is allowed to fully discharge. Which of these graphs represents the voltage versus time for that capacitor? 19. Consider these wires with the currents as labeled. What is the magnitude and direction of I? a. 20 A to the left b. 35 A to the right c. 10 A to the left d. 25 A to the right a. A b. B c. C d. D 22. A battery has an internal resistance of 2. Its ideal electromotive force is 20 V. If the current coming off of the battery is 5 A, what is the terminal voltage of the battery? a. 10 V b. 15 V c. 20 V d. 30 V e. 35 V ` 3
23. Consider this circuit. Which of the equations is a correct use of the loop rule? 26. For the previous circuit, which resistor has the larger voltage? a. 1 b. top 2 c. bottom 2 d. either the top or bottom 2 e. all have the same voltage a. -I 1 R 1 -I 4 R 4 -V=0 b. V-I 1 R 1 -I 2 R 2 -I 3 R 3 =0 c. +I 3 R 3 -I 2 R 2 =0 d. +I 2 R 2 -I 1 R 1 -V=0 24. Consider this circuit. What is the current through the 10 resistor? a. 10 A b. 2 A c. 5 A d. 1 A 25. Consider this circuit. What happens to the total current if you remove the 1 resistor? a. Total current increases b. Total current decreases c. Total current is the same d. Total current is zero 4
ID: A Exam 3--PHYS 102--S14 Answer Section MULTIPLE CHOICE 1. ANS: A PTS: 1 2. ANS: C PTS: 1 3. ANS: D PTS: 1 4. ANS: C PTS: 1 5. ANS: D PTS: 1 6. ANS: D PTS: 1 7. ANS: B PTS: 1 8. ANS: C PTS: 1 9. ANS: B PTS: 1 10. ANS: D PTS: 1 11. ANS: A PTS: 1 12. ANS: B PTS: 1 13. ANS: B PTS: 1 14. ANS: B PTS: 1 15. ANS: B PTS: 1 16. ANS: C PTS: 1 17. ANS: C PTS: 1 18. ANS: C PTS: 1 19. ANS: D PTS: 1 20. ANS: C PTS: 1 21. ANS: A PTS: 1 22. ANS: A PTS: 1 23. ANS: C PTS: 1 24. ANS: D PTS: 1 25. ANS: A PTS: 1 26. ANS: E PTS: 1 1