Download Your time has expired. Submit the assessment now or you may be

1.
A function is continuous but its first derivative has a finite discontinuity at the origin. What is your estimate of
the rolloff rate?
A) 1/ƒ
B) 1/ƒ2
C) 1/ƒ3
D) ƒ2
2.
A function with impulses has no rolloff.
A) True
B) False
3.
A rectangular pulse of height H is defined for -A/2 < t < A/2. Find the frequency domain representation X(ƒ).
A)
B)
C)
D)
HA
sin  Af
 Af
4.
A signal is given by x(t) = 1200 + 100 cos 2000πt + 240 cos 4000πt − 620 cos 6000πt. What is the dc
component? What is the second harmonic?
A) 100, 1 kHz
B) 1200, 1 kHz
C) 1200, 2 kHz
D) 1200, 3 kHz
5.
A system is characterized by a transfer function. What is the natural response of the circuit?
A) h(t) = e5t
B) h(t) = 5et
C) h(t) = e-5t
D) h(t) = sin 5t
6.
A system is characterized by a transfer function. What is the natural response of the circuit?
A) h(t) = e5t
B) h(t) = 5et
C) h(t) = e-5t cos 2t
D) h(t) = e-5t sin 2t
7.
A system is characterized by a transfer function.
What is the response function of the circuit in the s domain?
It is excited by a signal ƒ = cos 2t.
A)
B)
C)
D)
8.
A voltage source is v(t) = 200 sin (377t + 70 °). Write the phasor representation of this voltage.
A) V = 200 <: 377
B) V = 200 < (377 + 70)
C) V = 200 < (377t + 70)
D) V = 200 < 70
9.
An impedance Z = 10 + j20. What is the conductance?
A) 10 S
B) 20 S
C) 0.02 S
D) 0.04 S
10.
As the frequency of a signal increases:
A) The resistance of a capacitor increases.
B) The resistance of a capacitor decreases.
C) The resistance of a capacitor is unaffected.
D) The capacitor becomes purely reactive.
11.
As the frequency of a signal increases:
A) The resistance of an inductor increases.
B) The resistance of an inductor decreases.
C) The resistance of an inductor is unaffected.
D) The inductor becomes purely reactive.
12.
Consider the different representations of a Fourier series. The coefficients used in a cosine or sine series are
related to the coefficients in the cosine-sine form in what way?
A)
B)
C)
D)
13.
Differentiation in the time domain translates into:
A) Multiplication in the frequency domain.
B) Division in the frequency domain.
C) Superposition in the frequency domain.
D) Differentiation in the frequency domain.
14.
If v1 = 170 sin (377t +30°) and v2 = 170 sin (377t + 5°), then v1 leads v2 by 25 degrees.
A) True.
B) False.
15.
If a function is even, then its Fourier transform can be written as:
A)
B)
C)
D)
16.
If
, are there any poles? Is the system stable?
A) No, it is not stable.
B) Yes, it is impulse stable, pole at +3.
C) Yes, it is impulse stable, pole at -3.
D) Yes, it is impulse stable, pole at 0.
17.
If
, is the system stable?
A) No
B) Yes, it is impulse stable.
C) Yes, but it is only conditionally stable.
D) It is not BIBO stable.
18.
Suppose that Y = 0.15 − j0.17. What is the conductance? What is the susceptance? Is it inductive or
capacitive?
A) 0.15, -0.17, inductive
B) 0.15, -01.7, capacitive
C) -0.17, 0.15, inductive
D) -0.17, 0.15, capacitive
19.
The current flowing through a 10 H inductor is i = 20 sin (20t). What is the inductive reactance?
A) 20
B) 10
C) 200
D) ½
20.
The function x(t) = A cos t sin 2t is an even function.
A) True
B) False
21.
The voltage across a 10 ohm resistor is v(t) = 100 sin (50t + 20°). Find the current and write it in phasor
notation.
A) I = 100 20
B) I = 10 20
C) I = 1000 20
D) I = 10 -20
22.
The voltage across a load is v(t) = 200 sin (377t + 70°) and the current through the load is i(t) = 20 sin (377t
+ 20°). What is the impedance?
A) Z = 10 50 °
B) Z = 10 90 °
C) Z = 220 50 °
D) Z = 110 50 °
23.
The voltage across a load is v(t) = 260 sin (377t + 10 °). What is the RMS voltage?
A) 184 V
B) 120 V
C) 260 V
D) 377 V
24.
The voltage across a load is v(t) = 260 sin (377t + 10 °) and the current through the load is i = 100 sin (377t
+ 10°). What is the RMS power?
A) 13000 W.
B) 130 W.
C) It is undefined.
D) 10 W.
25.
What kind of circuit is equivalent to Z = 10 + j30?
A) A 10Ω resistor in series with a j30Ω capacitor.
B) A 10Ω resistor in series with a j30Ω inductor.
C) A 10Ω resistor in parallel with a j30Ω inductor.
D) A 10Ω resistor in parallel with a j30Ω capacitor.