Chapter 2, Problem 2. Find the hot resistance of a lightbulb rated 60 W, 120 V. Chapter 2, Problem 3. A bar of silicon is 4 cm long with a circular cross section. If the resistance of the bar is 240 at room temperature, what is the cross-sectional radius of the bar? Chapter 2, Problem 4. (a) Calculate current i in Fig. 2.68 when the switch is in position 1. (b) Find the current when the switch is in position 2. 2 1 100 150 i 15V + Figure 2.68 Chapter 2, Problem 7. Find the number of branches and nodes in each of the circuits of Fig. 2.71. 12V 1 2 2 -+ 1A 4V + _ 5 4A 3 3 1 10 5 (a) (b) Figure 2.71 Chapter 2, Problem 9. Find i1 , i 2 , and i3 in Fig. 2.73. 8A 2A 10 A i2 12 A B A i3 14 A i1 C 4A Figure 2.73 Chapter 2, Problem 11. In the circuit of Fig. 2.75, calculate V1 and V2. + 1V – + 2V – + + + V1 5V V2 _ _ _ Figure 2.75 Chapter 2, Problem 13. For the circuit in Fig. 2.77, use KCL to find the branch currents I1 to I4. Figure 2.77 Chapter 2, Problem 14. Given the circuit in Fig. 2.78, use KVL to find the branch voltages V1 to V4. Figure 2.78 Chapter 2, Problem 15. Calculate v and ix in the circuit of Fig. 2.79. 12 + v 12 V + _ + 8V – – ix + + 2V _ 3 ix _ Figure 2.79 Chapter 2, Problem 16. Determine Vo in the circuit in Fig. 2.80. 6 2 + 9V + _ Vo _ Figure 2.80 + _ 3V Chapter 2, Problem 21. Find Vx in the circuit of Fig. 2.85. 2 Vx 1 + 15 V – + + _ 5 Vx _ 2 Figure 2.85. Chapter 2, Problem 23. In the circuit shown in Fig. 2.87, determine vx and the power absorbed by the 12- resistor. Figure 2.87 Chapter 2, Problem 26. For the circuit in Fig. 2.90, io =2 A. Calculate ix and the total power dissipated by the circuit. ix io 2 4 Figure 2.90 8 16 Chapter 2, Problem 27. Calculate Vo in the circuit of Fig. 2.91. 4 + Vo - 16 V + _ 6 Figure 2.91 Chapter 2, Problem 29. All resistors in Fig. 2.93 are 1 each. Find Req. Req Figure 2.93 Chapter 2, Problem 30. Find Req for the circuit in Fig. 2.94. 6 6 2 Req 2 Figure 2.94 Chapter 2, Problem 31. For the circuit in Fig. 2.95, determine i1 to i5. 3 i1 i3 i2 40 V + _ 4 1 Figure 2.95 i4 2 i5 Chapter 2, Problem 34. Using series/parallel resistance combination, find the equivalent resistance seen by the source in the circuit of Fig. 2.98. Find the overall dissipated power. 20 8 10 + _ 12 V 40 40 20 12 10 Figure 2.98 Chapter 2, Problem 36. Find i and Vo in the circuit of Fig. 2.100. 10 24 i 50 25 15 V + _ 20 60 30 _ 20 Figure 2.100 Chapter 2, Problem 37. Find R for the circuit in Fig. 2.101. R 10 + 10 V – 20 V – + + _ Figure 2.101 + Vo 30 Chapter 2, Problem 38. Find Req and io in the circuit of Fig. 2.102. 60 12 5 io 6 80 40 V 15 + _ 20 Req Figure 2.102 Chapter 2, Problem 39. Evaluate Req for each of the circuits shown in Fig. 2.103. 6 k 2 k 1 k 4 k 12 k 2 k 1 k 12 k (a) (b) Figure 2.103 Chapter 2, Problem 44. For each of the circuits in Fig. 2.108, obtain the equivalent resistance at terminals a-b. Figure 2.108 Chapter 2, Problem 45. Find the equivalent resistance at terminals a-b of each circuit in Fig. 2.109. Figure 2.109 Chapter 2, Problem 46. Find I in the circuit of Fig. 2.110. 20 I 4 15 5 48 V + _ 15 15 24 8 Figure 2.110 Chapter 2, Problem 52. For the circuit shown in Fig. 2.116, find the equivalent resistance. All resistors are 1. Req Figure 2.116 Chapter 2, Problem 54. Consider the circuit in Fig. 2.118. Find the equivalent resistance at terminals: (a) a-b, (b) c-d. Figure 2.118 5 Chapter 2, Problem 63. If an ammeter with an internal resistance of 100 and a current capacity of 2 mA is to measure 5 A, determine the value of the resistance needed. Calculate the power dissipated in the shunt resistor. Chapter 2, Problem 66. A 20-k/V voltmeter reads 10 V full scale, (a) What series resistance is required to make the meter read 50 V full scale? (b) What power will the series resistor dissipate when the meter reads full scale? Chapter 2, Problem 70. (a) Consider the Wheatstone Bridge shown in Fig. 2.130. Calculate va , vb , and (b) Rework part (a) if the ground is placed at a instead of o. Figure 2.130 Chapter 2, Problem 71. Figure 2.131 represents a model of a solar photovoltaic panel. Given that vs = 30 V, R1 = 20 , IL = 1 A, find RL. Figure 2.131 Chapter 2, Problem 72. Find Vo in the two-way power divider circuit in Fig. 2.132. 1 1 1 Vo 10 V + _ 2 1 Figure 2.132 1 Chapter 2, Problem 77. Suppose your circuit laboratory has the following standard commercially available resistors in large quantities: 1.8 20 300 24 k 56 k Using series and parallel combinations and a minimum number of available resistors, how would you obtain the following resistances for an electronic circuit design? (a) 5 (b) 311.8 (c) 40 k (d) 52.32 k Chapter 2, Problem 78. In the circuit in Fig. 2.137, the wiper divides the potentiometer resistance between R and (1 )R, 0 1. Find vo / vs. R + vS vo + R αR Figure 2.137 Chapter 2, Problem 79. An electric pencil sharpener rated 240 mW, 6 V is connected to a 9-V battery as shown in Fig. 2.138. Calculate the value of the series-dropping resistor Rx needed to power the sharpener. Rs 9V Figure 2.138