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In parallel.
(e) It is used only for dc analysis.
(f) It does not correspond to a particular circuit
element.
Answers: 3.1a, 3.2c, 3.3b, 3.4d, 3.5c, 3.6a, 3.7d, 3.8b, 3.9c, 3.10b,d.
CHAPTER 4 Circuit Theorems
4.1 The current through a branch in a linear network is 2 A when the input source voltage is 10 V. If the voltage is reduced to 1 V and the polarity is reversed, the current through the branch is:
(a) −2
(b) −0. 2
(c) 0.2
(d) 2
(e) 20
4.2 For superposition, it is not required that only one independent source be considered at a time; any number of independent sources may be considered simultaneously.
(a) True
(b) False
4.3 The superposition principle applies to power calculation.
(a) True
(b) False
4.4 Refer to Fig. 4.67. The Thevenin resistance at terminals a and b is:
(a) 25 Ω
(b) 20 Ω
(c) 5 Ω
(d) 4 Ω
4.5 The Thevenin voltage across terminals a and b of the circuit in Fig. 4.67 is:
(a) 50 V
(b) 40 V
(c) 20 V
(d) 10 V
4.6 The Norton current at terminals a and b of the circuit in Fig. 4.67 is:
(a) 10 A
(b) 2.5 A
(c) 2 A
(d) 0 A
4.7 The Norton resistance RN is exactly equal to the Thevenin resistance R Th.
(a) True
(b) False
4.8 Which pair of circuits in Fig. 4.68 are equivalent?
(a) a and b
(b) b and d
(c) a and c
(d) c and d
4.9 A load is connected to a network. At the terminals to which the load is connected, R Th = 10 Ohmand V Th = 40 V. The maximum power supplied to the load is:
(a) 160 W
(b) 80 W
(c) 40 W
(d) 1 W
4.10 The source is supplying the maximum power to the load when the load resistance equals the source resistance.
(a) True
(b) False
Answers: 4.1b, 4.2a, 4.3b, 4.4d, 4.5b, 4.6a, 4.7a, 4.8c, 4.9c, 4.10b.
CHAPTER 5 Operational Amplifiers
5.1 The two input terminals of an op amp are labeled as:
(a) high and low.
(b) positive and negative.
(c) inverting and noninverting.
(d) differential and nondifferential.
5.2 For an ideal op amp, which of the following
statements are not true?
(a) The differential voltage across the input
terminals is zero.
(b) The current into the input terminals is zero.
(c) The current from the output terminal is zero.
(d) The input resistance is zero.
(e) The output resistance is zero.
5.3 For the circuit in Fig. 5.39, voltage vo is:
(a) −6 V
(b) −5 V
(c) −1. 2 V
(d) −0. 2 V
5.4 For the circuit in Fig. 5.39, current ix is:
(a) 0.6 A
(b) 0.5 A
(c) 0.2 A
(d) 1 / 12 A
5.5 If vs = 0 in the circuit of Fig. 5.40, current io is:
(a) −10 A
(b) −2. 5 A
(c) 10 / 12 A
(d) 10 / 14 A
5.6 If vs = 8 V in the circuit of Fig. 5.40, the output voltage is:
(a) −44 V
(b) −8 V
(c) 4 V
(d) 7 V
5.7 Refer to Fig. 5.40. If vs = 8 V, voltage va is:
(a) −8 V
(b) 0 V
(c) 10 / 3 V
(d) 8 V
5.8 The power absorbed by the 4-k _ resistor in Fig.
5.41 is:
(a) 9 mW
(b) 4 mW
(c) 2 mW
(d) 1 mW
5.9 Which of these amplifiers is used in a digital-to-analog converter?
(a) noninverter
(b) voltage follower
(c) summer
(d) difference amplifier
5.10 Difference amplifiers are used in:
(a) instrumentation amplifiers
(b) voltage followers
(c) voltage regulators
(d) buffers
(e) summing amplifiers
(f) subtracting amplifiers
Answers: 5.1c, 5.2c,d, 5.3b, 5.4b, 5.5a, 5.6c, 5.7d, 5.8b, 5.9c, 5.10a,f.
CHAPTER 6 Capacitors andInd uctors
6.1 What charge is on a 5-F capacitor when it is connected across a 120-V source?
(a) 600 C
(b) 300 C
(c) 24 C
(d) 12 C
6.2 Capacitance is measured in:
(a) coulombs
(b) joules
(c) henrys
(d) farads
6.3 When the total charge in a capacitor is doubled, the energy stored:
(a) remains the same
(b) is halved
(c) is doubled
(d) is quadrupled
6.4 Can the voltage waveform in Fig. 6.42 be associated with a capacitor?
(a) Yes
(b) No
6.5 The total capacitance of two 40-mF series-connected capacitors in parallel with a 4-mF capacitor is:
(a) 3.8 mF
(b) 5 mF
(c) 24 mF
(d) 44 mF
(e) 84 mF
6.6 In Fig. 6.43, if i =cos 4 t and v =sin 4 t, the element is:
(a) a resistor
(b) a capacitor
(c) an inductor
6.7 A 5-H inductor changes its current by 3 A in 0.2 s. The voltage produced at the terminals of the inductor is:
(a) 75 V
(b) 8.888 V
(c) 3 V
(d) 1.2 V
6.8 If the current through a 10-mH inductor increases from zero to 2 A, how much energy is stored in the inductor?
(a) 40 mJ
(b) 20 mJ
(c) 10 mJ
(d) 5 mJ
6.9 Inductors in parallel can be combined just like resistors in parallel.
(a) True
(b) False
Answers: 6.1a, 6.2d, 6.3d, 6.4b, 6.5c, 6.6b, 6.7a, 6.8b, 6.9a, 6.10d.
CHAPTER 7 First-Order Circuits
7.1 An RC circuit has R = 2 Ω and C = 4 F. The time constant is:
(a) 0.5 s
(b) 2 s
(c) 4 s
(d) 8 s
(e) 15 s
7.2 The time constant for an RL circuit with R = 2 Ω and L = 4 H is:
(a) 0.5 s
(b) 2 s
(c) 4 s
(d) 8 s
(e) 15 s
7.3 A capacitor in an RC circuit with R = 2 Ω and C = 4 F is being charged. The time required for the capacitor voltage to reach 63.2 percent of its steady-state value is:
(a) 2 s
(b) 4 s
(c) 8 s
(d) 16 s
(e) none of the above
7.4 An RL circuit has R = 2 Ω and L = 4 H. The time needed for the inductor current to reach 40 percent of its steady-state value is:
(a) 0.5 s
(b) 1 s
(c) 2 s
(d) 4 s
(e) none of the above
7.5 In the circuit of Fig. 7.79, the capacitor voltage just before t = 0 is:
(a) 10 V
(b) 7 V
(c) 6 V
(d) 4 V
(e) 0 V
7.6 In the circuit of Fig. 7.79, v( ∞ ) is:
(a) 10 V
(b) 7 V
(c) 6 V
(d) 4 V
(e) 0 V
7.7 For the circuit of Fig. 7.80, the inductor current just before t = 0 is:
(a) 8 A
(b) 6 A
(c) 4 A
(d) 2 A
(e) 0 A
7.8 In the circuit of Fig. 7.80, i( ∞ ) is:
(a) 8 A
(b) 6 A
(c) 4 A
(d) 2 A
(e) 0 A
7.9 If vs changes from 2 V to 4 V at t = 0, we may express vs as:
(a) δ(t) V
(b) 2 u(t) V
(c) 2 u( − t) + 4 u(t) V
(d) 2 + 2 u(t) V
(e) 4 u(t) − 2 V
7.10 The pulse in Fig. 7.110(a) can be expressed in terms of singularity functions as:
(a) 2 u(t) + 2 u(t − 1 ) V
(b) 2 u(t) − 2 u(t − 1 ) V
(c) 2 u(t) − 4 u(t − 1 ) V
(d) 2 u(t) + 4 u(t − 1 ) V
Answers: 7.1d, 7.2b, 7.3c, 7.4b, 7.5d, 7.6a, 7.7c, 7.8e, 7.9c,d, 7.10b.
CHAPTER 8 Second-Order Circuits
8.1 For the circuit in Fig. 8.58, the capacitor voltage at t = 0− (just before the switch is closed) is:
(a) 0 V
(b) 4 V
(c) 8 V
(d) 12 V
8.2 For the circuit in Fig. 8.58, the initial inductor current (at t = 0) is:
(a) 0 A
(b) 2 A
(c) 6 A
(d) 12 A
8.3 When a step input is applied to a second-order circuit, the final values of the circuit variables are found by:
(a) Replacing capacitors with closed circuits and inductors with open circuits.
(b) Replacing capacitors with open circuits and inductors with closed circuits.
(c) Doing neither of the above.
Correct answer is d
8.5 In a series RLC circuit, setting R = 0 will produce:
(a) an overdamped response
(b) a critically damped response
(c) an underdamped response
(d) an undamped response
(e) none of the above
8.6 A parallel RLC circuit has L = 2 H and C = 0. 25 F. The value of R that will produce unity damping factor is:
(a) 0. 5 Ohm
(b) 1 Ohm
(c) 2 Ohm
(d) 4 Ohm
8.7 Refer to the series RLC circuit in Fig. 8.59. What kind of response will it produce?
(a) overdamped
(b) underdamped
(c) critically damped
(d) none of the above
8.8 Consider the parallel RLC circuit in Fig. 8.60. What type of response will it produce?
(a) overdamped
(b) underdamped
(c) critically damped
(d) none of the above
8.9 Match the circuits in Fig. 8.61 with the following items:
(i) first-order circuit – c
(ii) second-order series circuit – b, e
(iii) second-order parallel circuit – a
(iv) none of the above – d, f
8.10 In an electric circuit, the dual of resistance is:
(a) conductance
(b) inductance
(c) capacitance
(d) open circuit
(e) short circuit
Answers: 8.1a, 8.2c, 8.3b, 8.4d, 8.5d, 8.6c, 8.7b, 8.8b, 8.9 (i)-c, (ii)-b,e, (iii)-a, (iv)-d,f, 8.10a.
CHAPTER 9 Sinusoids and Phasors
9.1 Which of the following is not a right way to express the sinusoid A cos ωt?
(a) A cos 2 πf t
(b) A cos ( 2 πt/T)
(c) A cos ω(t − T)
(d) A sin (ωt − 90° )
9.2 A function that repeats itself after fixed intervals is said to be:
(a) a phasor
(b) harmonic
(c) periodic
(d) reactive
9.3 Which of these frequencies has the shorter period?
(a) 1 krad/s
(b) 1 kHz
9.4 If v 1 = 30 sin (ωt + 10° ) and v 2 = 20 sin (ωt + 50° ),
which of these statements are true?
(a) v 1 leads v 2
(b) v 2 leads v 1
(c) v 2 lags v 1
(d) v 1 lags v 2
(e) v 1 and v 2 are in phase
9.5 The voltage across an inductor leads the current through it by 90°.
(a) True
(b) False
9.6 The imaginary part of impedance is called:
(a) resistance
(b) admittance
(c) susceptance
(d) conductance
(e) reactance
9.7 The impedance of a capacitor increases with increasing frequency.
(a) True
(b) False
9.8 At what frequency will the output voltage vo(t) in Fig. 9.39 be equal to the input voltage v(t)?
(a) 0 rad/s
(b) 1 rad/s
(c) 4 rad/s
(d) ∞rad/s
(e) none of the above
9.9 A series RC circuit has VR = 12 V and VC = 5 V. The supply voltage is:
(a) −7 V
(b) 7 V
(c) 13 V
(d) 17 V
9.10 A series RCL circuit has R = 30 Ω, XC =−50 Ω, and XL = 90 Ω. The impedance of the circuit is:
(a) 30 + j 140 Ω
(b) 30 + j 40 Ω
(c) 30 − j 40 Ω
(d) −30 − j 40 Ω
(e) −30 + j 40 Ω
Answers: 9.1d, 9.2c, 9.3b, 9.4b,d, 9.5a, 9.6e, 9.7b, 9.8d, 9.9c, 9.10b.
CHAPTER 10 Sinusoidal Steady-State Analysis
10.3 Using nodal analysis, the value of V o in the circuit of Fig. 10.45 is:
(a) −24 V
(b) −8 V
(c) 8 V
(d) 24 V
10.4 In the circuit of Fig. 10.46, current i(t) is:
(a) 10 cos t A
(b) 10 sin t A
(c) 5 cos t A
(d) 5 sin t A
(e) 4. 472 cos (t − 63. 43◦ ) A
10.5 Refer to the circuit in Fig. 10.47 and observe that the two sources do not have the same frequency. The current ix (t) can be obtained by:
(a) source transformation
(b) the superposition theorem
(c) PSpice
10.6 For the circuit in Fig. 10.48, the Thevenin impedance at terminals a - b is:
(a) 1 Ω
(b) 0. 5 − j 0. 5 Ω
(c) 0. 5 + j 0. 5 Ω
(d) 1 + j 2 Ω
(e) 1 − j 2 Ω
10.10 PSpice can handle a circuit with two independent sources of different frequencies.
(a) True
(b) False
Answers: 10.1c, 10.2a, 10.3d, 10.4a, 10.5b, 10.6c, 10.7a, 10.8a, 10.9d, 10.10b.
CHAPTER 11 AC Power Analysis
11.1 The average power absorbed by an inductor is zero.
(a) True
(b) False
11.2 The Thevenin impedance of a network seen from the load terminals is 80 + j 55 Ω. For maximum power transfer, the load impedance must be:
(a) −80 + j 55 Ω
(b) −80 − j 55 Ω
(c) 80 − j 55 Ω
(d) 80 + j 55 Ω
11.3 The amplitude of the voltage available in the 60-Hz, 120-V power outlet in your home is:
(a) 110 V
(b) 120 V
(c) 170 V
(d) 210 V
11.5 A quantity that contains all the power information in a given load is the
(a) power factor
(b) apparent power
(c) average power
(d) reactive power
(e) complex power
11.6 Reactive power is measured in:
(a) watts
(b) VA
(c) VAR
(d) none of these
11.7 In the power triangle shown in Fig. 11.34(a), the reactive power is:
(a) 1000 VAR leading
(b) 1000 VAR lagging
(c) 866 VAR leading
(d) 866 VAR lagging
11.8 For the power triangle in Fig. 11.34(b), the apparent power is:
(a) 2000 VA
(b) 1000 VAR
(c) 866 VAR
(d) 500 VAR
11.9 A source is connected to three loads Z 1, Z 2, and Z 3 in parallel. Which of these is not true?
(a) P = P 1 + P 2 + P 3
(b) Q = Q 1 + Q 2 + Q 3
(c) S = S 1 + S 2 + S 3
(d) S = S1 + S2 + S3
11.10 The instrument for measuring average power is the:
(a) voltmeter
(b) ammeter
(c) wattmeter
(d) varmeter
(e) kilowatt-hour meter
Answers: 11.1a, 11.2c, 11.3c, 11.4d, 11.5e, 11.6c, 11.7d, 11.8a, 11.9c, 11.10c.
CHAPTER 12 Three-Phase Circuits
12.4 In a Y-connected load, the line current and phase current are equal.
(a) True
(b) False
12.5 In a -connected load, the line current and phase current are equal.
(a) True
(b) False
12.6 In a Y-Y system, a line voltage of 220 V produces a phase voltage of:
(a) 381 V
(b) 311 V
(c) 220 V
(d) 156 V
(e) 127 V
12.7 In a ∆- ∆system, a phase voltage of 100 V produces a line voltage of:
(a) 58 V
(b) 71 V
(c) 100 V
(d) 173 V
(e) 141 V
12.8 When a Y-connected load is supplied by voltages in abc phase sequence, the line voltages lag the corresponding phase voltages by 30◦.
(a) True
(b) False
12.9 In a balanced three-phase circuit, the total instantaneous power is equal to the average power.
(a) True
(b) False
12.10 The total power supplied to a balanced ∆-load is found in the same way as for a balanced Y-load.
(a) True
(b) False
Answers: 12.1a, 12.2a, 12.3c, 12.4a, 12.5b, 12.6e, 12.7c, 12.8b, 12.9a, 12.10a.
CHAPTER 13 Magnetically Coupled Circuits
13.1 Refer to the two magnetically coupled coils of Fig. 13.69(a). The polarity of the mutual voltage is:
(a) Positive
(b) Negative
13.2 For the two magnetically coupled coils of Fig. 13.69(b), the polarity of the mutual voltage is:
(a) Positive
(b) Negative
13.3 The coefficient of coupling for two coils having L 1 = 2 H, L 2 = 8 H, M = 3 H is:
(a) 0.1875
(b) 0.75
(c) 1.333
(d) 5.333
13.4 A transformer is used in stepping down or stepping up:
(a) dc voltages
(b) ac voltages
(c) both dc and ac voltage
13.5 The ideal transformer in Fig. 13.70(a) has N 2 /N 1 = 10. The ratio V 2 /V 1 is:
(a) 10
(b) 0.1
(c) −0. 1
(d) −10
13.6 For the ideal transformer in Fig. 13.70(b), N 2 /N 1 = 10. The ratio I 2 /I 1 is:
(a) 10
(b) 0.1
(c) −0. 1
(d) −10
13.7 A three-winding transformer is connected as portrayed in Fig. 13.71(a). The value of the output voltage Vo is:
(a) 10
(b) 6
(c) −6
(d) −10 
13.8 If the three-winding transformer is connected as in Fig. 13.71(b), the value of the output voltage Vo is:
(a) 10
(b) 6
(c) −6
(d) −10
13.9 In order to match a source with internal impedance of 500 Ω to a 15- Ω load, what is needed is:
(a) step-up linear transformer
(b) step-down linear transformer
(c) step-up ideal transformer
(d) step-down ideal transformer
(e) autotransformer
13.10 Which of these transformers can be used as an isolation device?
(a) linear transformer
(b) ideal transformer
(c) autotransformer
(d) all of the above
Answers: 13.1b, 13.2a, 13.3b, 13.4b, 13.5d, 13.6b, 13.7c, 13.8a, 13.9d, 13.10b.
CHAPTER 14 Frequency Response
14.1 A zero of the transfer function
is at
(a) 10
(b) −1
(c) −2
(d) −3
14.2 On the Bode magnitude plot, the slope of the pole 1 /( 5 + jω) 2 is
(a) 20 dB/decade
(b) 40 dB/decade
(c) −40 dB/decade
(d) −20 dB/decade
14.3 On the Bode phase plot, the slope of [1 + j 10 ω − ω 2 / 25]2 is
(a) 45◦/decade
(b) 90◦/decade
(c) 135◦/decade
(d) 180◦/decade
14.4 How much inductance is needed to resonate at 5 kHz with a capacitance of 12 nF?
(a) 2652 H
(b) 11.844 H
(c) 3.333 H
(d) 84.43 mH
14.5 The difference between the half-power frequencies is called the:
(a) quality factor
(b) resonant frequency
(c) bandwidth
(d) cutoff frequency
14.6 In a series RLC circuit, which of these quality factors has the steepest curve at resonance?
(a) Q = 20
(b) Q = 12
(c) Q = 8
(d) Q = 4
14.7 In a parallel RLC circuit, the bandwidth B is directly proportional to R.
(a) True
(b) False
14.8 When the elements of an RLC circuit are both magnitude-scaled and frequency-scaled, which quality is unaffected?
(a) resistor
(b) resonant frequency
(c) bandwidth
(d) quality factor
14.9 What kind of filter can be used to select a signal of one particular radio station?
(a) lowpass
(b) highpass
(c) bandpass
(d) bandstop
14.10 A voltage source supplies a signal of constant amplitude, from 0 to 40 kHz, to an RC lowpass filter. The load resistor experiences the maximum voltage at:
(a) dc
(b) 10 kHz
(c) 20 kHz
(d) 40 kHz
Answers: 14.1b, 14.2c, 14.3d, 14.4d, 14.5c, 14.6a, 14.7b, 14.8d, 14.9c, 14.10a.
CHAPTER 15 The Laplace Transform
15.1 Every function f (t) has a Laplace transform.
(a) True
(b) False
15.2 The variable s in the Laplace transform H(s) is called
(a) complex frequency
(b) transfer function
(c) zero
(d) pole
15.3 The Laplace transform of u(t − 2 ) is:
15.4 The zero of the function
is at
(a)−4
(b) −3
(c) −2
(d) −1
15.5 The poles of the function
are at
(a)−4
(b) −3
(c) −2
(d) −1
15.6 If F(s) = 1 /(s + 2 ), then f (t) is
(a) e 2 t u(t)
(b) e −2 t u(t)
(c) u(t − 2 )
(d) u(t + 2 )
15.10 A transfer function is defined only when all initial conditions are zero.
(a) True
(b) False
Answers: 15.1b, 15.2a, 15.3d, 15.4d, 15.5a,b,c, 15.6b, 15.7b, 15.8d, 15.9c, 15.10b.
CHAPTER 16 The Fourier Series 757
16.5 If f (t) = 10 + 8 cos t + 4 cos 3 t + 2 cos 5 t +…, the magnitude of the dc component is:
(a) 10
(b) 8
(c) 4
(d) 2
(e) 0
16.6 If f (t) = 10 + 8 cos t + 4 cos 3 t + 2 cos 5 t +…, the angular frequency of the 6th harmonic is
(a) 12
(b) 11
(c) 9
(d) 6
(e) 1
16.7 The function in Fig. 16.14 is half-wave symmetric.
(a) True
(b) False
16.8 The plot of | cn | versus nω 0 is called:
(a) complex frequency spectrum
(b) complex amplitude spectrum
(c) complex phase spectrum
16.9 When the periodic voltage 2 + 6 sin ω 0 t is applied to a 1- Ω resistor, the integer closest to the power (in watts) dissipated in the resistor is:
(a) 5
(b) 8
(c) 20
(d) 22
(e) 40
16.10 The instrument for displaying the spectrum of a signal is known as:
(a) oscilloscope
(b) spectrogram
(c) spectrum analyzer
(d) Fourier spectrometer
Answers: 16.1a,d, 16.2b, 16.3b,c,d, 16.4d,e, 16.5a, 16.6d, 16.7a, 16.8b, 16.9d,16.10c.
CHAPTER 17 Fourier Transform
Answers: 17.1c, 17.2c, 17.3d, 17.4d, 17.5b, 17.6c, 17.7b, 17.8b, 17.9d, 17.10b
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