Chapter 18 Direct Current Circuits CHAPTER 18 Conceptual Questions C1 Three resistors each of different value are used in a circuit with a power source supplying 12 volts For which of the following resistor combinations is the total power supplied the greatest a all three resistors in series b all three resistors in parallel c two of the resistors in parallel with the third resistor in series with the parallel pair d This cannot be found until it is known which resistor is in series with the parallel pair C2 Kirchhoff s rules are the junction rule and the loop rule Which of the following statements is true a Both rules are based on the conservation of charge b Both rules are based on the conservation of energy c The junction rule is based on the conservation of charge and the loop rule is based on the conservation of energy d The junction rule is based on the conservation of energy and the loop rule is based on the conservation of charge C3 Using a capacitor and two different value resistors which of the following combinations in an RC circuit would give the greatest time constant a the capacitor in series with both resistors in series with each other b the capacitor in series with both resistors in parallel with each other c the capacitor in series with the higher value resistor d the capacitor in series with the lower value resistor C4 Using a resistor and two different value capacitors which of the following combinations in an RC circuit would give the greatest time constant a the resistor in series with both capacitors in series with each other b the resistor in series with both capacitors in parallel with each other c the resistor in series with the larger value capacitor d the resistor in series with the lower value capacitor C5 In an RC circuit using two capacitors in series with two resistors which of the following combinations would give the greatest time constant 51 Chapter 18 Direct Current Circuits a both capacitors in series placed in series with both resistors in series b both capacitors in parallel placed in series with both resistors in parallel c both capacitors in series placed in series with both resistors in parallel d both capacitors in parallel placed in series with both resistors in series 18 1 Sources of emf 18 2 Resistors in Series 18 3 Resistors in Parallel 1 The two ends of a 3 0 resistor are connected to a 9 0 V battery What is the current through the resistor a 27 A b 6 3 A c 3 0 A d 0 33 A 2 The two ends of a 3 0 resistor are connected to a 9 0 V battery What is the total power delivered by the battery to the circuit a 3 0 W b 27 W c 0 33 W d 0 11 W 3 The basic function of an electromotive force in a circuit is to do which of the following a Convert electrical energy into some other form b Convert some other form of energy into electrical c Both choices a and b are valid d None of the above choices are valid 4 Which voltage is not caused by a source of emf a the voltage across a charged capacitor b the voltage across two copper iron junctions at different temperatures c the voltage across the terminals of a dry cell battery d the voltage from an electric generator 5 The internal resistances of an ideal voltmeter and an ideal ammeter are respectively ideal meaning the behavior of the system is not changed when using the meter 52 Chapter 18 Direct Current Circuits a zero and zero b infinite and infinite c zero and infinite d infinite and zero 53 Chapter 18 Direct Current Circuits 6 When a 24 0 resistor is connected across a 12 0 V battery a current of 482 mA flows What is the internal resistance of the battery a 0 02 b 0 9 c 25 0 d 49 8 7 When a 24 0 resistor is connected across a 12 0 V battery a current of 482 mA flows What is the power output delivered by the emf of the battery a 0 21 W b 5 57 W c 5 78 W d 6 00 W 8 When a 24 0 resistor is connected across a 12 0 V battery a current of 482 mA flows What is the resulting terminal voltage of the battery a 0 4 V b 5 8 V c 11 6 V d 12 0 V 9 Three 8 0 resistors are connected in series What is their equivalent resistance a 24 0 b 8 0 c 0 38 d 0 13 10 Three resistors connected in series each carry currents labeled I1 I2 and I3 Which of the following expresses the value of the total current IT in the system made up of the three resistors in series a IT I1 I2 I3 b IT 1 I1 1 I2 1 I3 c IT I1 I2 I3 d IT 1 I1 1 I2 1 I3 1 11 Three resistors connected in series have individual voltages labeled V1 V2 and V3 respectively Which of the following expresses the value of the total voltage VT taken over the three resistors together 54 Chapter 18 Direct Current Circuits a VT V1 V2 V3 b VT 1 V1 1 V2 1 V3 c VT V1 V2 V3 d VT 1 V1 1 V2 1 V3 1 12 Three resistors with values of R1 R2 and R3 respectively are connected in series Which of the following expresses the total resistance RT of the three resistors a RT R1 R2 R3 b RT 1 R1 1 R2 1 R3 c RT R1 R2 R3 d RT 1 R1 1 R2 1 R3 1 13 Three resistors with values of 2 0 4 0 and 8 0 respectively are connected in series What is the overall resistance of this combination a 0 58 b 1 1 c 7 0 d 14 0 14 Which resistor is in series with resistor R R a R1 b R2 c R3 d R4 R4 R1 R2 R3 15 Three resistors each with resistance R1 are in series in a circuit They are replaced by one equivalent resistor R Comparing this resistor to the first resistor of the initial circuit which of the following is true a The current through R equals the current through R1 b The voltage across R equals the voltage across R1 c The power given off by R equals the power given off by R1 d R is less than R1 16 If R1 R2 R3 and if these resistors are connected in series in a circuit which one dissipates the greatest power a R1 b R2 55 Chapter 18 Direct Current Circuits c R3 d All are equal in power dissipation 17 When a light bulb is turned on its resistance increases until it reaches operating temperature What happens to the current in the bulb as it is warming up a It …