6. What is the value of the hypotenuse of a right triangle whose sides are 12 and 18?
(a) 4.24
(b) 3.46
(c) 2.16
(d) 21.63
7. A 120 Ω resistor is in parallel with a capacitor with a capacitive reactance of 40 Ω. Both components are across a 12 V ac source. What is the magnitude of the total impedance?
(a) 37.9 Ω
(b) 3.7 Ω
(c) 14,400 Ω
(d) 4,800 Ω
8. A 2 kΩ resistor is in series with a 0.015 μF capacitor across a 15 kHz ac source. What is the magnitude of the total impedance and the phase angle?
(a) 73.4 Ω and θ = –19.5°
(b) 707 Ω and θ = –19.5°
(c) 2121 Ω and θ = –19.5°
(d) 734 Ω and θ = –38.9°
9. A 47 Ω resistor and a capacitor with 150 Ω of capacitive reactance are in series across an ac source. The impedance, expressed in rectangular form, is ________.
(a) Z = 47 Ω + j150 Ω
(b) Z = 47 Ω – j150 Ω
(c) Z = 197 Ω
(d) Z = 103 Ω
10. A 12 kΩ resistor is in series with a 0.02 μF capacitor across a 1.2 kHz ac source. If the current is expressed in polar form as I = 0.3 ∠0° mA, what is the source voltage expressed in polar form?
(a) 45.6 V
(b) 411.3 V
(c) 0.411 V
(d) 4.11 V
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5555555555 8. A 2 kΩ resistor is in series with a 0.015 μF capacitor across a 15 kHz ac source. What is the magnitude of the total impedance and the phase angle? (a) 73.4 Ω and θ = –19.5° (b) 707 Ω and θ = –19.5° (c) 2121 Ω and θ = –19.5° (d) 734 Ω and θ = –38.9°- 5555555555 19. A 47 Ω resistor and a capacitor with a capacitive reactance of 120 Ω are in series across an ac source. What is the circuit impedance, Z? (a) 129 Ω (b) 12.9 Ω (c) 167 Ω (d) 73 Ω
- 5555555555 11. A capacitor with 150 Ω of capacitive reactance is across an ac source. The impedance, expressed in polar form, is ________. (a) Z = 150 (b) Z = 150 ∠90° Ω (c) Z = 150 ∠–90° Ω (d) Z = 150 ∠180° Ω
- 5555555555 10. A 47 Ω resistor is in series with an inductive reactance of 120 Ω across an ac source. The impedance, expressed in polar form, is ________. (a) 47 ∠68.6° Ω (b) 120 ∠68.6° Ω (c) 129 ∠31.4° Ω (d) 129 ∠68.6° Ω
- 5555555555 10. A 200 Ω resistor, a coil with 30 Ω of reactance, and a capacitor of unknown reactance are in series across an ac source. The circuit is at resonance. Circuit impedance ________. (a) is 230 Ω (b) is 170 Ω (c) is 200 Ω (d) cannot be determined