Electric Circuits Exam

Transcription

1 Electric Circuits Exam 1. The diagram below represents a lamp, a 10-volt battery, and a length of nichrome wire connected in series. 4. Which circuit has the smallest equivalent resistance? A) B) As the temperature of the nichrome is decreased, the brightness of the lamp will A) decrease B) increase C) remain the same 2. The diagram below shows a circuit with three resistors. C) What is the resistance of resistor R3? A) 6.0 B) 2.0 C) 12 D) Base your answer to the following question on the diagram below, which shows two resistors and three ammeters connected to a voltage source. D) What is the current reading of ammeter A1? A) 10.0 A B) 6.0 A C) 3.0 A D) 4.0 A 5. What is the current in a wire if electrons pass by a point in this wire every 60. seconds? A) A B) A C) A D) 11 A 6. A charge of 30. coulombs passes through a 24-ohm resistor in 6.0 seconds. What is the current through the resistor? A) 1.3 A B) 5.0 A C) 7.5 A D) 4.0 A 7. How much electrical energy is required to move a 4.00-microcoulomb charge through a potential difference of 36.0 volts? A) J B) 144 J C) J D) J

2 8. Base your answer to the following question on the diagram below, which represents an electric circuit consisting of four resistors and a 12-volt battery. How much power is dissipated in the 36-ohm resistor? A) 110 W B) 48 W C) 3.0 W D) 4.0 W 9. In the circuit diagram below, ammeter A measures the current supplied by the 10.-volt battery. 11. Base your answer to the following question on the circuit diagram below. The current measured by ammeter A is A) 0.13 A B) 2.0 A C) 0.50 A D) 4.0 A 10. In the electric circuit diagram below, possible locations of an ammeter and a voltmeter are indicated by circles 1, 2, 3, and 4 Where should an ammeter be located to correctly measure the total current and where should a voltmeter be located to correctly measure the total voltage? A) ammeter at 1 and voltmeter at 4 B) ammeter at 2 and voltmeter at 3 C) ammeter at 3 and voltmeter at 4 D) ammeter at 1 and voltmeter at 2 The current through R1 will be A) less than 2 amperes B) 2 amperes C) more than 4 amperes D) 4 amperes 12. The current through a lightbulb is 2.0 amperes. How many coulombs of electric charge pass through the lightbulb in one minute? A) 60. C B) 2.0 C C) 120 C D) 240 C 13. In the circuit at the right, if an ammeter is moved from position 1 to position 2, the current measured will A) decrease B) increase C) remain the same

3 14. As the potential difference across a given resistor is increased, the power expended in moving charge through the resistor A) decreases B) increases C) remains the same 15. A manufacturer recommends that the longer the extension cord used with an electric drill, the thicker (heavier gauge) the extension cord should be. This recommendation is made because the resistance of a wire varies A) directly with length and inversely with cross-sectional area B) inversely with length and directly with cross-sectional area C) directly with both length and cross-sectional area D) inversely with both length and cross-sectional area 16. Base your answer to the following question on the diagram of the circuit below. 17. The resistance of a circuit remains constant. Which graph best represents the relationship between the current in the circuit and the potential difference provided by the battery? A) B) C) D) If resistance R2 were removed, the potential difference across R1 would A) decrease B) increase C) remain the same 18. If 60. joules of work are required to move 5.0 coulombs of charge between two points in an electric field, what is the potential difference between these points? A) 5.0 V B) 12 V C) 60. V D) 300 V 19. Ammeters A1, A2 and A3 are placed in a circuit as shown below. What is the reading on ammeter A3? A) 1.0 A B) 2.0 A C) 3.0 A D) 5.0 A

4 20. The potential difference applied to a circuit element remains constant as the resistance of the element is varied. Which graph best represents the relationship between power (P) and resistance (R) of this element? A) B) 22. Base your answer to the following question on the diagram below. The reading of voltmeter V1 is 26 volts, and the reading of ammeter A1 is 2 amperes. C) D) 21. A 6.0-ohm lamp requires 0.25 ampere of current to operate. In which circuit below would the lamp operate correctly when switch S is closed? A) What is the total resistance of the circuit? A) B) C) D) 23. Base your answer to the following question on the diagram below. B) C) D) What is the total resistance of the circuit? A) W B) 2.00 W C) 3.00 W D) 4.00 W 24. A 3-ohm resistor and a 6-ohm resistor are connected in parallel across a 9-volt battery. Which statement best compares the potential difference across each resistor? A) The potential difference across the 6-ohm resistor is the same as the potential difference across the 3-ohm resistor. B) The potential difference across the 6-ohm resistor is twice as great as the potential difference across the 3-ohm resistor. C) The potential difference across the 6-ohm resistor is half as great as the potential difference across the 3-ohm resistor. D) The potential difference across the 6-ohm resistor is four times as great as the potential difference across the 3-ohm resistor.

5 25. In the circuit diagram below, what are the correct readings of voltmeters V1 and V2? A) V1 reads 2.0 V and V2 reads 4.0 V B) V1 reads 4.0 V and V2 reads 2.0 V C) V1 reads 3.0 V and V2 reads 3.0 V D) V1 reads 6.0 V and V2 reads 6.0 V 26. Plastic insulation surrounds a wire having diameter d and length as shown below. A decrease in the resistance of the wire would be produced by an increase in the A) thickness of the plastic insolation B) length of the wire C) diameter d of the wire D) temperature of the wire 27. An electric circuit consists of a variable resistor connected to a source of constant potential difference. If the resistance of the resistor is doubled, the current through the resistor is A) halved B) doubled C) quartered D) quadrupled 28. The diagram below shows three resistors, R1, R2, and R 3, connected to a 12-volt battery. If voltmeter V1 reads 3 volts and voltmeter V2 reads 4 volts, what is the potential drop across resistor R3? A) 12 V B) 5 V C) 0 V D) 4 V

6 29. In which circuit would current flow through resistor R 1, but not through resistor R 2 while switch S is open? A) B) C) D) 30. An electric iron operating at 120 volts draws 10. amperes of current. How much heat energy is delivered by the iron in 30. seconds? A) J B) J C) J D) J 31. What is the resistance at 20.ºC of a 2.0-meter length of tungsten wire with a cross-sectional area of meter 2? A) B) C) D) Which condition must exist between two points in a conductor in order to maintain a flow of charge? A) a potential difference B) a magnetic field C) a low resistance D) a high resistance 33. The diagram below represents a series circuit containing three resistors. 34. The current through a 10.-ohm resistor is 1.2 amperes. What is the potential difference across the resistor? A) 8.3 V B) 12 V C) 14 V D) 120 V 35. How much energy is required to move coulomb of charge through a potential difference of 5 volts? A) 5 ev B) 2 ev C) 10 ev D) 20 ev What is the current through resistor R2? A) 1.0 A B) 0.33 A C) 3.0 A D) 9.0 A