Exit Exam Model from EPCE

Prévia do material em texto

Choose a correct answer accordingly. 
1. A passive network is one which contains: 
a) Only variable resistance 
b) Only some sources of e.m.f. in it 
c) Only two sources of e.m.f. in it 
d) No source of e.m.f. in it 
2. Which of the following is not the properties of transfer function? 
a) all initial conditions of the system are set to zero 
b) The transfer function is dependent on the input of the system 
c) It is defined only for a linear time-invariant system 
d) The transfer function between an input variable and an output variable of a 
system is defined as the Laplace transform of the impulse response 
3. The poles and zeros of driving point impedance function and driving point 
admittance function lie on 
a) Left half of s-plane 
b) Right half of s-plane 
c) Left half of s-plane or on imaginary axis 
d) Right half of s-plane or imaginary axis 
4. In non-linear network does not satisfy 
a) Superposition condition 
b) Homogeneity condition 
c) Both homogeneity and superposition condition 
d) Homogeneity, superposition and associative condition 
5. Which of the following is true about band stop filters? 
a) Obtained by parallel connection of low pass and high pass filters. 
b) Obtained by cascade connection of low pass and high pass filters. 
c) Cut off frequency of high pass filter must be less than low pass filter. 
d) All 
6. A filter that passes all frequencies lying outside a certain range, while it attenuates 
all frequencies between the two designated frequencies is called? 
a) low pass filter 
b) high pass filter 
c) band elimination filter 
d) band pass filter 
7. According to routh tabulation method, the system is said to be stable if there are no 
sign changes in the first column of the routh array, the number of poles lies on the 
left half of s-plane =number of sign changes. 
a) True 
b) False 
8. For the Reciprocity Theorem to satisfy the ratio of response to excitation before and 
after the source is replaced should be? 
a) Different 
b) Same 
c) before source is replaced is greater than after the source is replaced 
d) before source is replaced is less than after the source is replaced 
9. Which one the following true about symmetry theorem for the two port electrical 
networks. 
a) For z parameters open circuit driving point impedance must be equal to be 
symmetrical network. 
b) For Y parameters short circuit driving point admittance must be equal to be 
symmetrical network. 
c) For h and g parameters determinants of corresponding h and g parameters 
must be equal to 1 to be symmetrical network. 
d) All the above 
10. A network either T or π, is said to be of the constant-k type if Z1 and Z2 of the 
network satisfies the relation? 
a) Z1Z2 = k 
b) Z1Z2 = k2 
c) Z1Z2 = k3 
d) Z1Z2 = k4 
11. Determine the range of K so that the system given by characteristic equation. 
3 2S +3KS +(K+5)S+4=0 is stable. 
a. K 0.2537 
c. K > 0.528 
d. K39. The format used to present the logic output for the various combinations of logic 
inputs to a gate is called a(n): 
A. Boolean constant 
B. Boolean variable 
C. Truth table 
D. Logic function 
40. A logic probe is again applied to the pins of a 7421 IC with the following results. Is 
there a problem with the circuit and if so, what is the problem? 
PIN Indicator PIN Indicator 
1 ON 14 ON 
2 PULSING 13 ON 
3 DIM 12 ON 
4 ON 11 DIM 
5 ON 10 OFF 
6 PULSING 9 PULSING 
7 OFF 8 OFF 
A. Pin 6 should be ON 
B. Pin 8 should be ON. 
C. Pin 8 should be pulsing. 
D. no problem 
41. The circuit of the given figure-1 realizes the function 
A. (A’+B’)C+ (DE)’ 
B. A’+B’+C’+D’+E’ 
C. AB+C+DE 
D. AB+C(D+E) 
 
 Figure -1 
42. In the given figure-2, A = B = 1 and C = D = 0. Then Y = 
A. 0 
B. 1 
C. Either 0 or 1 
D. Indeterminate 
 
 Figure -2 
43. The logic circuit given figure -3 converts a binary code ABC into 
 
A. Excess-3 Code 
B. Gray Code 
C. BCD code 
D. Hamming Code 
 
 Figure - 3 
44. Which of the following Boolean algebra statements represent distributive law 
A. A+BC = A.B + A.C 
B. A + BC = A(B+C) 
C. A + BC = (A+B).C 
D. A + BC = (A + B) (A + C) 
45. Which one of the following gives the simplified sum of products expression for the 
Boolean function F = m0 + m2 + m3 + m5, where m0, m2, m3 and m5 are minterms 
corresponding to the inputs X, Y and Z with X as the MSB and Z as the LSB? 
A. X’Y+ X’Y’Z’+ XY’Z 
B. X’Z’+ XY’+ XY’Z 
C. X’Z’+ X’Y+ XY’Z 
D. X’YZ+ X’Z’+ XY’Z 
46. Consider the 2-bit multiplexer (MUX) shown in the figure-4. For OUTPUT to be the 
XOR of C and D, the values for A0, A1, A2 and A3 are ___________. 
A. A0 = 0, A1= 0, A2 =1,A3 =1 
B. A0 = 1, A1= 0, A2 =1,A3 =0 
C. A0 = 0, A1= 1, A2 =1,A3 =0 
D. A0 = 1, A1= 1, A2 =0, A3 =0 
 
 
 Figure - 4 
47. The Boolean function realized by the logic circuit shown 
figure-5 is 
A. F =  m( 0,1,3,5,9,10,14) 
B. F =  m( 2,3,5,7,8,12,13) 
C. F =  m( 1,2,4,5,11,14,15) 
D. F =  m( 2,3,5,7,8,9,12) 
 Figure – 5 
 
 
48. A gated S-R latch and its associated waveforms are shown figure-6. What, if 
anything, is wrong and what could be causing the problem? 
A. The 𝑸 ̅̅̅output is always low; the 
circuit is defective. 
B. The 𝑄 output should be the 
complement of the 𝑄 ̅ output; 
the S and R terminals are reversed. 
C. The Q should be following 
the R input; the R input is defective. 
D. There is wrong with the 𝑄 output circuit Figure - 6 
49. What is the major difference between half-adders and full-adders? 
A. Nothing basically; full-adders are made up of two half-adders. 
B. Full adders can handle double-digit numbers. 
C. Full adders have a carry input capability. 
D. Half adders can handle only single-digit numbers. 
50. In the latch circuit shown figure-7, the NAND gates have non-zero, but unequal 
propagation delays. The present input condition is: P = Q = “0”. If the input condition 
is changed simultaneously to P = Q = "1", the outputs X and Y are 
A. X= 1 , Y= 1 
B. Either X= 0 , Y= 1 or X= 1 , Y= 0 
C. Either X= 1 , Y= 1 or X= 0 , Y= 0 
D. X= 0 , Y= 0 
 
 
 
 Figure - 7 
51. Which one the following is true about signal and system analysis 
a. A system is a set of fixed rules that relates an output time signals to its input 
signal 
b. Usable information is conveyed through signal 
c. A shift in the input signal does not exhibit the corresponding shift in the output 
d. A system is a mathematical operator which maps input into output 
52. Most of the signals found in nature are ________ 
a. Continuous-time and discrete-time 
b. Continuous-time and digital 
 
c. Digital and Analog 
e. Analog and Continuous-time 
53. If a signal 𝑥(𝑡) 𝑢(𝑡) is shifted to left side by 𝑡0,then the function can be expressed as 
a. 𝑥(𝑡 – 𝑡0) 𝑢(𝑡) 
b. 𝑥(𝑡) 𝑢(𝑡 – 𝑡0) 
c. 𝑥(𝑡 – 𝑡0) 𝑢(𝑡 – 𝑡0) 
d. 𝑥(𝑡 + t0) u(t + t0) 
54. When we take up design of systems, ideally how do we define the stability of a 
system? 
a. A system is stable, if a bounded input gives a bounded output, for some values of 
the input. 
b. A system is unstable, if a bounded input gives a bounded output, for all values of 
the input. 
c. A system is stable, if a bounded input gives a bounded output, for all values of 
the input. 
d. A system is unstable, if a bounded input gives a bounded output, for some values 
of the input. 
55. The system 𝑦(𝑡)=𝑥(𝑡)cos (𝑡+1) is 
a. Not memoryless and causal 
b. Not memoryless and not causal 
c. Memoryless and causal 
d. Memoryless and not causal 
56. Consider a continuous-time system with input 𝑥(𝑡) and output y(t) given by 𝑦(𝑡) =
 𝑥(𝑡)𝑐𝑜𝑠𝑡. The system is: 
a. Linear and Time-invariant 
b. Non-linear and Time-invariant 
c. Linear and Time-varying 
d. Non-linear and Time-varying 
57. The homogeneous solution of the differential equation 𝑑𝑦(𝑡)𝑑𝑡+𝑎𝑦(𝑡)=𝑥(𝑡) will be of 
a. 𝐶𝑒𝑎𝑡 
b. 𝐶1𝑒𝑎𝑡 + 𝐶2𝑒−𝑎𝑡 
c. 𝐶1 + 𝐶2𝑒−𝑎𝑡 
d. 𝐶𝑒−𝑎𝑡 
58. Two systems with impulse responses ℎ1(𝑡) and ℎ2(𝑡) are connected in cascade. 
Then the overall impulse response of the cascaded system is given by: 
a. Product of ℎ1(𝑡) and ℎ2(𝑡) 
b. Sum of ℎ1(𝑡)and ℎ2(𝑡) 
c. Convolution of ℎ1(𝑡) and ℎ2(𝑡) 
d. Subtraction of ℎ1(𝑡) and ℎ2(𝑡) 
 
59. The result of 𝑢(𝑡) ∗ 𝑢(𝑡) is, where 𝑢(𝑡) is unit step signal: 
a. 𝑢2(𝑡) b. 𝑡𝑢(𝑡) c. 𝑡2𝑢(𝑡) d. 𝛿(𝑡)
60. Which one of the following is correct on properties of Laplace transform? 
a. ∫ 𝑥(𝜏)𝑑𝜏 ↔
𝑡
−∞
1
𝑠
𝑋(𝑠) 
b. 𝑥(𝑎𝑡) ↔ 𝑋(𝑠) 
c. 𝑒𝑠0𝑥(𝑡) ↔ 𝑋(𝑠0) 
d. 
𝑑
𝑑𝑡
𝑥(𝑡) ↔
1
𝑠
𝑋(𝑠) 
61. The initial value of 𝑓(𝑡) with Laplace transform 𝐹(𝑠) = 
𝑆+1
(𝑆+2)(𝑆+3)
 is:
a. Nonexistent 
b. ∞ 
c. 0 
d. 1 
62. The inverse Laplace transform of 𝐹(𝑠) = 
𝑆+2
(𝑆+2)2+1
 is: 
a. 𝑒−𝑡𝑐𝑜𝑠2𝑡 b. 𝑒−𝑡𝑠𝑖𝑛2𝑡 c. 𝑒−2𝑡𝑠𝑖𝑛2𝑡 d. 𝑒−2𝑡𝑐𝑜𝑠2𝑡 
63. Which one the following is not true about Fourier Series 
a. A mathematical tool that allows representation of any periodic signal as the sum 
of harmonically related sinusoids 
b. A shift in time domain is equivalent to introducing phase shift in Fourier Series 
c. Odd periodic signals have only sine terms of Fourier Series 
d. Compression of a signal in time domain is equivalent to compression in Fourier 
Series 
64. Which of the following cannot be a Fourier series? 
a. 5𝑠𝑖𝑛𝑡 + 3𝑠𝑖𝑛2𝑡 − 2𝑠𝑖𝑛3𝑡 + 𝑠𝑖𝑛4𝑡 
b. 𝑆𝑖𝑛𝑡 − 2𝑐𝑜𝑠3𝑡 + 4𝑠𝑖𝑛4𝑡 + 𝑐𝑜𝑠4𝑡 
c. 𝑆𝑖𝑛𝑡 + 3𝑠𝑖𝑛2.7𝑡 − 𝑐𝑜𝑠𝜋𝑡 + 2𝑡𝑎𝑛𝜋𝑡 
d. 1 + 𝑒−𝑗𝜔 + 
𝑒−𝑗2𝜋𝑡
2
+ 
𝑒−𝑗3𝜋𝑡
3
 
65. In the Fourier transform, if the time domain signal 𝑥(𝑡) is real and even, then the 
frequency domain signal 𝑋(𝜔) will be: 
a. Imaginary and even 
b. Imaginary and odd 
c. Real and Even 
d. Real and odd 
66. Which of these functions does not have a Fourier transform? 
a. 1
𝑡⁄ 
b. 𝑡𝑒−3𝑡𝑢(𝑡) 
c. 𝑒𝑡𝑢(−𝑡) 
d. |𝑡|𝑢(𝑡)
 
67. What type of materials is formed when trivalent material is doped with silicon or 
germanium? 
a. N type 
b. N and P typec. PN type 
d. P type 
68. The term “fully saturation” for a transistor refers to: 
a. The collector current at its maximum value. 
b. The collector current at minimum value 
c. The transistors beta at its maximum value 
d. The transistors alpha at its maximum value 
69. Common base amplifier has___________compared to common emitter and common 
collector amplifiers. 
a. A higher input resistance 
b. A larger current gain 
c. A lower input resistance 
d. A larger voltage gain 
70. In an intrinsic semiconductor which one of the following alternative is true? 
a. Free electrons are thermally generated 
b. Minority charge carriers are holes 
c. Majority charge carriers are holes 
d. None 
71. How to forward bias a PN junction diode? 
a. By applying an external voltage that is positive to the n-region and negative to 
the p-region 
b. By applying an external voltage that is positive to the p-region and negative to 
the n-region 
c. By applying an external voltage that is positive to the cathode and negative to 
the anode 
d. By applying an external voltage that is positive to both anode and cathode 
72. Which one of the following is the most unstable biasing technique in basic transistor 
amplifiers? 
a. Limited bias 
b. Combination bias 
c. Self-bias 
d. Base current fixed bias 
73. Which of the following rectifier needs a transformer for its operation? 
a. half-wave rectifier 
b. Centre-tap full-wave rectifier 
c. bridge full-wave rectifier 
d. none of the above 
 
74. The theoretical maximum efficiency of a Bridge rectifier circuit is 
a. 48.2%. 
b. 82%. 
c. 81.2%. 
d. 40.6%. 
75. The extremely high input impedance of a MOSFET is primarily due to ….. 
a. Absence of its channel. 
b. Negative gate-source voltage. 
c. Depletion of current carriers. 
d. Extremely small leakage current of its gate capacitor. 
76. In a BJT, if the emitter junction is reverse-biased and the collector junction is 
reverse-biased, it is said to operate in 
a. in active region 
b. in saturation region 
c. in cut-off region 
d. none of the above 
77. In a common-emitter transistor amplifier circuit ẞ = 100, input resistance R₁ = 1 kΩ, 
output resistance R2 = 10 kΩ. The voltage gain of circuit is: 
a. 100 
b. 1000 
c. 10 
d. 5000 
78. Consider the common emitter amplifier shown below figure with the following 
circuit parameters: 
Β=100, 𝑔𝑚 = 0.3861 𝐴
𝑉⁄ , 𝑟𝑜 = 259Ω, 𝑅𝑠 = 1𝑘Ω, 𝑅𝐵 = 93𝑘Ω, 𝑅𝐶 = 250𝑘Ω, 𝑅𝐿 = 1000𝑘Ω, 
𝐶1 = ∞ and 𝐶2 = 4.7𝜇𝐹. 
The lower cut -off frequency due to C2 is 
a. 33.9 Hz 
b. 27.1 Hz 
c. 13.6 Hz 
d. 16.9 Hz 
 
 
 
 
 
 
 
 
 Figure 1 
 
79. A half-wave rectifier has an input voltage of 240 V r.m.s. If the step-down 
transformer has a turns ratio of 8:1, what is the peak load voltage? Ignore diode 
drop. 
a. 27.5 V 
b. 86.5 V 
c. 30 V 
d. 42.5 V 
80. With the positive probe on an NPN base, an ohmmeter reading between the other 
transistor terminals should be: 
a. Open 
b. infinite 
c. low resistance 
d. high resistance 
81. The gain band width product, thermal stability and the relation between input and 
output of FET compared to BJT is respectively 
a. High, low linear 
b. Low, low, non-linear 
c. Low, high, linear 
d. Low, high, nonlinear 
82. What is the typical value for the input impedance Zi for JFETs? 
a. 100K OHM 
b. 1 M OHM 
c. 10 M OHM 
d. 1000 M OHM 
83. This is an example of the output swing for a class _______________________ amplifier 
a. A. 
b. B. 
c. AB 
d. C 
 
84. Which of the following is (are) not power amplifiers? 
a. Class A 
b. Class B or AB 
c. Class C or D 
d. Feedback amplifier 
85. Which one of the following is a component of computer system which manages the 
entire function of computer system? 
a. Memory unit 
b. Input /output unit 
c. Arithmetic Logic Unit 
d. Control Unit 
 
86. Which one of the following is the function of computer that connect all of the 
components so that they may communicate and work? 
a. Mother Board 
b. Graphics Processing Unit (GPU) 
c. Operating System 
d. Central Processing Unit (CPU) 
87. In programming a set of instructions or rules designed to solve a given problem 
with finite number of steps is called? 
a. Coding 
b. Algorithm 
c. Implementation 
d. Analysis 
88. In programming, a function which repeats itself is called? 
a. Inline function 
b. Recursive function 
c. Predicate function 
d. Faction declaration 
89. What will be the output of the following Python code? 
1. >>>list1 = [1, 3] 
2. >>>list2 = list1 
3. >>>list1[0] = 4 
4. >>>print(list2) 
a. [1, 4] 
b. [1, 3, 4] 
c. [1, 3] 
d. [4, 3] 
90. What will be the value of’ list 3 in following Python program? 
list1 = [1,2,3,4] 
list2 = [2,4,5,6] 
list3 = [2,6,7,8] 
 list1.append(list2) 
 list1.pop(6) 
 list3.append(list1[1-6] 
print list3 
a. [2, 3, 4, 2, 4] 
b. [1, 2, 3, 4, 2,4,6] 
c. [2, 6, 7, 8] 
d. [1, 2, 3, 4] 
91. Which of the following statements is wrong about inheritance? 
a. Protected members of a class can be inherited 
b. The inheriting class is called a subclass 
 
c. Private members of a class can be inherited and accessed 
d. Inheritance is one of the features of OOP 
92. What will be the output of the following Python code? 
def test(i,j): 
 if(i==0): 
 return j 
 else: 
 return test (i-1, i + j) 
 print (test(4,7)) 
 
a. 13 
b. 7 
c. Infinite loop 
d. 17 
93. Which of the following best describes polymorphism? 
A. Ability of a class to derive members of another class as a part of its own 
definition 
B. Means of bundling instance variables and methods in order to restrict access 
to certain class members 
C. Focuses on variables and passing of variables to functions 
D. Allows for objects of different types and behavior to be treated as the same 
general type 
94. One of the following is characteristics of computer that can perform different kinds 
of works with same accuracy and efficiency. 
A. Versatility 
B. Diligence 
C. Speed 
D. Accuracy 
95. Which register holds the address of the current instruction being executed? 
A. Instruction register 
B. Memory data register (MDR) 
C. Stack register 
D. Program counter 
 
96. Which of the following is not a valid variable name in most programming languages? 
A. Abc123 
B. 123abc 
C. _abc 
D. abc_def 
97. One of the following is a program which is used to convert codes of high-level 
language into machine language and it scan all line at a time? 
A. Assembler 
B. Interpreter 
C. Compiler 
D. Debugger 
98. Which of the following is used to measure the speed of the CPU (processor)? 
A. Processing speed 
B. Unit 
C. Coprocessor 
D. Clock speed 
99. What will be the output of the following programming code? 
i = 0 
while i