7. How long must a 100-watt light bulb be used in order to dissipate 1,000 joules of electrical energy? 1) 10 s 3) 1,000 s 2) 100 s 4) 100,000 s

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1 1. Which quantity must be the same for each component in any series circuit? 1) power 3) current 2) resistance 4) voltage 2. A student needs a 4-ohm resistor to complete a circuit. Only a large quantity of 1-ohm resistors are available. Which of the following should be done to complete the circuit? 1) Connect four 1-ohm resistors in parallel. 2) Connect only two 1-ohm resistors in parallel. 3) Connect two of the 1-ohm resistors in series and two in parallel. 4) Connect four 1-ohm resistors in series. 7. How long must a 100-watt light bulb be used in order to dissipate 1,000 joules of electrical energy? 1) 10 s 3) 1,000 s 2) 100 s 4) 100,000 s 8. If 60. electrons pass a given point in a conductor in one second, the current in this conductor is 1) A 3) A 2) A 4) A 9. In the circuit represented by the diagram below, what is the reading of voltmeter V? 3. A 10.-ohm resistor and a 20.-ohm resistor are connected in series to a voltage source. When the current through the 10.- ohm resistor is 2.0 amperes, what is the current through the 20.-ohm resistor? 1) 1.0 A 3) 0.50 A 2) 2.0 A 4) 4.0 A 4. What is the total resistance of the circuit segment shown in the diagram below? 1) 20. V 3) 30. V 2) 2.0 V 4) 40. V 10. In a flashlight, a battery provides a total of 3.0 volts to a bulb. If the flashlight bulb has an operating resistance of 5.0 ohms, the current through the bulb is 1) 1.7 A 3) 0.60 A 2) 0.30 A 4) 1.5 A 11. What is the current in the circuit represented in the diagram below? 1) 1.0 Þ 3) 3.0 Þ 2) 9.0 Þ 4) 27 Þ 5. Two identical resistors connected in series have an equivalent resistance of 4 ohms. The same two resistors, when connected in parallel, have an equivalent resistance of 1) 1 Þ 3) 8 Þ 2) 2 Þ 4) 4 Þ 1) 1 A 3) 3 A 2) 2 A 4) 6 A 6. A complete circuit is left on for several minutes, causing the connecting copper wire to become hot. As the temperature of the wire increases, the electrical resistance of the wire 1) decreases 3) remains the same 2) increases

2 12. Ammeters A 1, A 2 and A 3 are placed in a circuit as shown below. 16. The diagram below shows a resistor of 5 ohms and a resistor of 10 ohms connected in parallel in a circuit. What is the total resistance of the circuit? What is the reading on ammeter A 3? 1) 1.0 A 3) 3.0 A 2) 2.0 A 4) 5.0 A 13. In the circuit diagram shown below, what is the current through the 4.0-ohm resistor? 1) less than 5 ohms 3) 15 ohms 2) 5 ohms 4) greater than 15 ohms 17. A 12-volt battery is connected to resistors R 1 and R 2 as shown in the diagram below. If the reading of voltmeter V 1 is 8 volts, what is the reading of voltmeter V 2? 1) 1.0 ampere 3) 3.0 amperes 2) 0.33 ampere 4) 48 amperes 14. In the circuit shown at the right, the potential difference across the 4.0-ohm resistor is 1) 20. volts 3) 8 volts 2) 12 volts 4) 4 volts 18. While operating at 120 volts, an electric toaster has a resistance of 15 ohms. The power used by the toaster is 1) 8.0 W 3) 960 W 2) 120 W 4) 1,800 W 19. What is the resistance at 20.ºC of a 2.0-meter length of tungsten wire with a cross-sectional area of meter 2? 1) Þ 3) Þ 2) Þ 4) Þ 1) 6.0 volts 3) 3.0 volts 2) 2.0 volts 4) 12 volts 15. The resistance of a 60.-watt lightbulb operated at 120 volts is approximately 1) 720 Þ 3) 120 Þ 2) 240 Þ 4) 60. Þ 20. When three 30-ohm resistors are connected in parallel across a 9-volt source, the total current is 1) 0.10 A 3) 0.45 A 2) 0.30 A 4) 0.90 A 21. A lamp operates at 10 volts and draws a current of.5 ampere for 60 seconds. What power is developed by the lamp? 1) 5 watts 3) 300 watts 2) 30 watts 4) 600 watts

3 22. Which circuit diagram below correctly shows the connection of ammeter A and voltmeter V to measure the current through and potential difference across resistor R? 1) 2) 3) 25. A copper wire of length L and cross-sectional area A has resistance R. A second copper wire at the same temperature has a length of 2L and a cross-sectional area of 1 2A. What is the resistance of the second copper wire? 1) 2R 2) 4R 3) R 4) 1 R What is the total electrical energy used by a 1500-watt hair dryer operating for 6.0 minutes? 1) 4.2 J 3) J 2) 250 J 4) J 27. Three ammeters are located near junction P in a direct current circuit as shown in the diagram below. 4) If ammeter A l reads 3 amperes and ammeter A 2 reads 4 amperes, then what does ammeter A 3 read? 1) 5 A 3) 3 A 2) 7 A 4) 8 A 23. As the number of resistors in a parallel circuit is increased, what happens to the equivalent resistance of the circuit and total current in the circuit? 1) Both equivalent resistance and total current decrease. 2) Equivalent resistance decreases and total current increases. 3) Both equivalent resistance and total current increase. 4) Equivalent resistance increases and total current decreases. 24. The current through a lightbulb is 2.0 amperes. How many coulombs of electric charge pass through the lightbulb in one minute? 1) 60. C 3) 120 C 2) 2.0 C 4) 240 C 28. A piece of wire has a resistance of 8 ohms. A second piece of wire of the same composition, diameter, and temperature, but one-half as long as the first wire, has a resistance of 1) 8 3) 16 2) 2 4) A copper wire has a resistance of 200 ohms. A second copper wire with twice the cross-sectional area and the same length would have a resistance of 1) 50 3) 200 2) 100 4) 400

4 30. A copper wire is part of a complete circuit through which current flows. Which graph best represents the relationship between the wire's length and its resistance? 1) 31. A potential difference of 12 volts is applied across a circuit which has a 4.0-ohm resistance. What is the magnitude of the current in the circuit? 1) 0.33 A 3) 3.0 A 2) 48 A 4) 4.0 A 32. A charge of 5.0 coulombs moves through a circuit in 0.50 second. The current in the circuit is 1) 7.0 A 3) 2.5 A 2) 5.0 A 4) 10. A 2) 33. The graph at the right shows how the voltage and current are related in a simple electric circuit. For any point on the line, what does the ratio of V to I represent? 1) power in watts 3) charge in coulombs 2) resistance in ohms 4) work in joules 3) 4)

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6 Answer Key electrity test a [Mar 31, 2009]