* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Exam 2
Integrated circuit wikipedia , lookup
Power electronics wikipedia , lookup
Transistor–transistor logic wikipedia , lookup
Negative resistance wikipedia , lookup
Index of electronics articles wikipedia , lookup
Lumped element model wikipedia , lookup
Operational amplifier wikipedia , lookup
Galvanometer wikipedia , lookup
Valve RF amplifier wikipedia , lookup
Power MOSFET wikipedia , lookup
Switched-mode power supply wikipedia , lookup
Surge protector wikipedia , lookup
Two-port network wikipedia , lookup
Resistive opto-isolator wikipedia , lookup
Opto-isolator wikipedia , lookup
Rectiverter wikipedia , lookup
Current mirror wikipedia , lookup
RLC circuit wikipedia , lookup
Current source wikipedia , lookup
Electrical ballast wikipedia , lookup
Name: ________________________ Class: ___________________ Date: __________ ID: Z Exam 2 Multiple Choice Identify the choice that best completes the statement or answers the question. ____ ____ 1. You wish to measure a current through a resistor. You should connect the measuring device in what way? a. in series with the resistor c. replace the resistor with the measuring device b. in parallel with the resistor d. it depends on the circuit 2. A current of 20 A flows through a wire of length 1 m and diameter 1 mm. The potential across the wire is 1.4 V. From this table of resistivities, select the material of the wire: Material Copper Silver Gold Tungsten Iron ____ ____ ____ ____ Resistivity(Ohm-m) 1.7x10-8 1.59x10-8 2.44x10-8 5.5x10-8 10.0x10-8 a. Copper d. Tungsten b. Silver e. Iron c. Gold 3. A 3 V potential difference is maintained across a 10 Ω resistor for 2 minutes. How many electrons pass through the material? d. 0.3 a. 2.25x1020 b. 60 e. 36 c. 3.75x1018 4. Nonohmic materials a. all of the above c. do not obey Ohm’s Law b. do not include most resistors d. include diodes 5. A one-hundred watt lightbulb and a 50-watt lightbulb are in parallel with a power supply of 100 V. What current flows through the 100 W light bulb? a. 1/2 A c. None of the above b. 2 A d. 1 A 6. A 50Ω and a 100Ω resistor are in series with a power supply of 150 V. What amount of energy is dissipated across the 50 Ω resistor in 3 seconds? a. 300 J c. 450 J b. 100 J d. 150 J 1 Name: ________________________ ____ ____ ____ ID: Z 7. The electric company charges a rate of $0.10 per kilowatt-hour. How much does it cost to run a 100 W bulb for 10 hours? a. $1 c. $0.36 b. $10 d. $0.10 8. On a circuit breaker, you have a 1200 W heater, a 60 W light bulb, and a 240 W radio. When you add a 180 W blender, the circuit breaker turns off. Assume all the devices operate at 120 V. Which of these is the maximum allowed current for the breaker? a. 20 A c. 10 A b. 13 A d. 15 A 9. Two wires, A and B, are made of the same metal and have equal length, but the resistance of wire A is 16 times the resistance of wire B. How do their diameters compare? a. dA=dB d. b. dA=2dB e. dA=4dB 1 dA= dB 2 1 dA= dB 4 ____ 10. When you rotate the knob of a light dimmer, what is being changed in the electric circuit? c. a. resistance d. just power & current b. current e. all of the above c. power ____ 11. In your house, two lightbulbs operate at 120 V, but one has a power rating of 25 W while the other has a power rating of 100 W. Which one has the greater current flowing through it? a. 25 W bulb c. both have same current b. not enough information d. 100 W bulb ____ 12. Two space heaters in your living room are operated at 120 V. Heater 1 has twice the resistance of heater 2. Which one will give off more heat? a. b. Heater 1 Heater 2 c. d. 2 both will give same heat not enough information Name: ________________________ ID: Z ____ 13. A battery has an internal resistance of 1 Ω. When it provides a current of 2 A, the potential across the battery is 10 V. What is the ideal electromotive force provided by the battery? a. 5 V c. b. 12 V d. ____ 14. What is the equivalent resistance of this circuit? 30 V 20 V a. 5.6 Ω c. 5.1 Ω b. 25 Ω d. 4.1 Ω ____ 15. Two resistors of 7 Ω and 3Ω are in series with a 10 V battery. What is the current through the 3 Ω resistor? a. b. 3.33 A 1A c. d. 3 1.4 A 0.3 A Name: ________________________ ID: Z ____ 16. Three resistors of 2 Ω, 4Ω , and 4Ω are in parallel with a power supply of 10 V. What is the total current through the circuit? a. 2.5 A c. 10 A b. 5 A d. 1 A ____ 17. The ammeter in this circuit reads a current of I 3=1 A. What is the current I 1? a. b. 1.1 A 1.25 A c. d. 4 1.4 A 2.9 A Name: ________________________ ID: Z ____ 18. Which of these equations is appropriate (ie. correct) for this circuit? a. b. c. 10-6I2-2I3=0 I1+I3=I2 2I3+6I1-10=0 d. e. 5 14+6I1-10-4I2=0 14-4I2+2I3=0 Name: ________________________ ID: Z ____ 19. In this circuit, what happens to the current in each resistor as you add resistors in parallel? a. Current decreases c. It depends on the value of the added resistance b. Current stays the same d. Current increases ____ 20. In this circuit, what happens to the brightness of bulb A when you close the switch? a. b. not enough information glows brighter than before c. d. 6 glows just the same as before glows less than before Name: ________________________ ID: Z ____ 21. In this figure, light bulbs A, B, and C each have a resistance of 1 Ω . How do the brightness of bulbs A and C compare? a. b. c. bulb A is four times as bright as C bulb A is twice as bright as C bulb A is 1/2 as bright as C d. e. bulb A is the same brightness as C bulb A is 1/4 as bright as C ____ 22. When 2 or more resistors are connected in parallel to a battery, a. all of the above b. the voltage across each resistor is the c. the equivalent resistance of the combination is less than or equal to the resistance of any one of the resistors d. the total current flowing from the battery equals the sum of the currents flowing through each resistor same ____ 23. Three identical resistors are connected in series to an ideal battery with V=12 V. What is the potential across each resistor? a. b. 4V 2V c. d. 7 3V 6V Name: ________________________ ID: Z ____ 24. In this RC circuit, the time constant is 1 µs and the resistance is 10 Ω. What is the capacitance, C? a. b. c. 2 µF 0.1 µC 10 µF d. e. 1 µF 0.1 µF ____ 25. What happens to the voltage across the resistor R 1 when the switch is closed? The voltage will: a. b. decrease increase c. d. 8 stay the same not enough information given Name: ________________________ ID: Z ____ 26. What happens to the current through the resistor R 1 when the switch S is closed? R1 S R3 V R4 R2 a. decreases c. stays the same b. increases ____ 27. Assume each of these resistances are identical. Which resistor(s) has the least amount of current flowing through it? V a. b. c. R5 R2 R5 both R3 and R4 equally both R1 and R2 equally R4 R3 R1 d. e. R1 all the same ____ 28. What purpose does the third prong on a three-prong outlet serve? a. Allow for more stability in the outlet c. Act as a ground thus providing a safety feature b. An alternative to the European system d. of electrical outlets No purpose ____ 29. GFCI stands for a. Gauge for Circuit Integrity c. Good For Cashing In b. Ground Force Circuit Interpreter d. Ground Fault Circuit Interrupt ____ 30. A household circuit has all of the electrical devices connected in _____________. a. it depends on the house c. series b. parallel d. a combination of series and parallel ____ 31. The correct answer to this question is “A.” Please write “A” above your name on the scantron. a. A c. C b. B d. D 9 ID: Z Exam 2 Answer Section MULTIPLE CHOICE 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: A D A A D D D B C E D B B C B C C C B B A A A E B B B C D B A PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1