1. Which one of the following is NOT a valid rule of Boolean algebra?
Correct : A. a = a\
2. In the binary number ' 10011 ' the weight of the most significant digit is
Correct : A. 2^4(2 raise to power 4)
3. The binary value ' 1010110 ' is equivalent to decimal
Correct : A. 86
4. 2's complement of hexadecimal number B70A is
Correct : C. 48f6
5. 2's complement of 5 is
Correct : B. 1011
6. The 4-bit 2's complement representation of ' -7 ' is
Correct : C. 1001
7. If we multiply ' 723 ' and ' 34 ' by representing them in floating point notation i.e. By first, converting them in floating point representation and then multiplying them, the value of mantissa of result will be
Correct : A. 24.582
8. The output of the expression F=A+B+C will be Logic when A=0, B=1, C=1. the symbol ' + ' here represents OR Gate.
Correct : B. one
9. A NAND gate's output is LOW if
Correct : C. any input is low
10. NOR gate is formed by connecting
Correct : C. and gate and then or gate
11. The AND Gate performs a logical function
Correct : C. multiplicatio
12. The Extended ASCII Code (American Standard Code for Information Interchange) is a code
Correct : C. 8-bit
13. The OR gate performs Boolean .
Correct : D. addition
14. The output of an AND gate is one when
Correct : A. all of the inputs are one
15. A NOR's gate output is HIGH if
Correct : D. all inputs are
low
16. A logic circuit with an output X = A(Bar)BC+AB(Bar) consists of .
Correct : C. two and gates, one
or gate, two inverters
17. the boolean expression AB'CD'is
Correct : B. a product ter
18. The boolean expression X = AB + CD represents
Correct : C. two ands ored together
19. The expression is an example of Commutative Law for Multiplication.
Correct : C. ab=ba
20. The total amount of memory that is supported by any digital system depends upon
Correct : D. the size of the address bus of the microproc essor
21. Addition of two octal numbers “36” and “71” results in
Correct : C. 127
22. In which of the following base systems is 123 not a valid number?
Correct : D. base 3
23. Storage of 1 KB means the following number of bytes
Correct : D. 1064
24. What is the octal equivalent of the binary number: 10111101
Correct : B. 275
25. The binary code of (21.125)10 is
Correct : A. 10101.001
26. A NAND gate is called a universal logic element because
Correct : B. any logic function can be realized by nand gates alone
27. Digital computers are more widely used as compared to analog computers, because they are
Correct : C. useful over wider ranges of problem types
28. Most of the digital computers do not have floating point hardware because
Correct : A. floating point hardware is costly
29. The number 1000 would appear just immediately after
Correct : D. all of the
30. (1(10101)2 is
Correct : A. (37)10
31. The number of Boolean functions that can be generated by n variables is equal to
Correct : B. 22 n
32. Consider the representation of six-bit numbers by two’s complement, one’s
complement, or by sign and magnitude: In which representation is there overflow from
the addition of the integers 011000 and 011000?
Correct : D. all three representa tions.
33. Positive logic in a logic circuit is one in which
Correct : D. logic 0 voltage level is lower than logic 1 voltage level.
34. Which of the following gate is a two-level logic gate
Correct : C. exclusive
or gate
35. An AND gate will function as OR if
Correct : D. all the inputs and outputs are compleme nted.
36. An OR gate has 6 inputs. The number of input words in its truth table are
Correct : C. 64
37. NAND. gates are preferred over others because these
Correct : B. can be used to make any gate
38. In case of OR gate, no matter what the number of inputs, a
Correct : A. 1 at any input causes the
39. Excess-3 code is known as
Correct : C. self-
40. Indicate which of the following three binary additions are correct? 1.1011 + 1010 = 10101
II. 1010 + 1101 = 10111
III. 1010 + 1101 = 11111
Correct : D. ii and i
41. X – = Y + 1 means
Correct : A. x = x – y + 1
42. A binary digit is called a
Correct : A. bit
43. The ASCII code for letter A is
Correct : C. 1000001
44. Transistor is a
Correct : A. current controlled current device.
45. A digital logic device used as a buffer should have what input/output characteristics?
Correct : D. high input impedance and low output impedance
46. What is the standard TTL noise margin?
Correct : D. 0.4 v
47. The range of a valid LOW input is:
Correct : B. 0.4 v to 0.8 v
48. When an IC has two rows of parallel connecting pins, the device is referred to as:
Correct : B. a dip
49. Which digital IC package type makes the most efficient use of printed circuit board space?
Correct : A. smt
50. The digital logic family which has minimum power dissipation is
Correct : D. cmos
51. Which of the following is the fastest logic
Correct : B. ecl
52. The digital logic family which has the lowest propagation delay time is
Correct : A. ecl
53. Which TTL logic gate is used for wired ANDing
Correct : A. open collector output
54. CMOS circuits consume power
Correct : B. less than ttl
55. In a positive logic system, logic state 1 corresponds to
Correct : B. higher voltage level
56. The commercially available 8-input multiplexer integrated circuit in the TTL family is
Correct : B. 74153
57. The logic 0 level of a CMOS logic device is approximately
Correct : C. 0volts
58. Which ofthe following is a universal logic gate?
Correct : D. nand
59. How is the noise margin of a logic family defi ned?
Correct : C. smaller of vil – vol
and voh – vih
60. What parameter causes the main limit on fan-out of CMOS logic in high-speed applications?
Correct : A. d.c. input current
61. The number of standard loads that the output of the gate can drive with out impairment of its normal operation is
Correct : B. fan-out
62. Measure of power consumed by the gate when fully driven by all its inputs is
Correct : D. power- dissipiatio n
63. Fan-out is specified in terms of
Correct : D. unit load
64. Which of the following logic family has highest fan-out
Correct : B. cmos
65. Which of following consume minimum power
Correct : D. cmos
66. Among the logic families, low power dissipation is in
Correct : B. cmos
67. The temperature in which the performance of the IC is effective
Correct : A. operating
68. The nominal value of the dc supply voltage for TTL (transistor-transistor
logic) devices is
Correct : B. 5v
69. The average transition delay time for the signal to propagate from input to output when the signals change in value. It is expressed in ns is
Correct : A. propogation delay
70. the number of inputs connected to the gate without any degradation in the
Correct : C. fan- in
71. Which of the following logic gives the complementary outputs?
Correct : A. ecl
72. The maximum noise voltage added to an input signal of a digital circuit
Correct : C. noise-margin
73. Among the logic families, Slowest logic family is
Correct : D. cmos
74. Operating temperature of the IC vary from
Correct : A. 0 to70 celsius
75. 1. Open collector output 2. Totem-Pole Output 3. Tri-state output are the
type of
Correct : A. ttl logic
76. If the channel is initially doped lightly with p-type impurity a conducting
Correct : A. depletion
77. If the region beneath the gate is left initially uncharged the gate field must induce a
channel before current can flow. Thus the gate voltage enhances the
channel current and sucha device is said to operate in the
Correct : B. enhancemen t mode operation of
mos
78. The n- channel MOS conducts when its
Correct : A. gate- to- source voltage
79. The p- channel MOS conducts when its
Correct : C. gate- to-
80. The fan-out of a MOS-logic gate is higher than that of TTL gates because of its
Correct : D. high output impedance
81. Which factor does not affect CMOS loading?
Correct : C. output capacitance
82. Logic gates are the basic elements that make a
Correct : D. digital system
83. Which of the following gate is a two-level logic gate
Correct : C. exclusive
or gate
84. Among the logic families, the family which can be used at very high frequency greater than 100 MHz in a 4 bit
Correct : C. ecl
85. The fan Out of a 7400 NAND gate is
Correct : D. 10ttl
86. Which transistor element is used in CMOS logic?
Correct : B. mosfet
87. CMOS circuits are extensively used for ON-chip computers mainly because of their extremely
Correct : C. large packing density.
88. Which equation is correct?
Correct : D. vnh =
voh(min)
–
vih(min)
89. The greater the propagation delay, the
Correct : A. lower the maximum frequency
90. For a CMOS gate, which is the best speed-power product?
Correct : A. 1.4 pj
91. In a TTL circuit, if an excessive number of load gate inputs are connected,
Correct : B. voh drops below voh(min)
92. Which is not a MOSFET terminal?
Correct : D. base
93. An open-drain gate is the CMOS counterpart of
Correct : A. an open- collector ttl gate
94. The active switching element used in all TTL circuits is the
Correct : A. bipolar junction transistor (bjt
95. One output structure of a TTL gate is often referred to as a
Correct : C. totem-pole arrangement
96. An open-collector output requires
Correct : B. a pull-up resistor
97. Which is not an output state for tristate logic?
Correct : D. low-z
98. TTL is alive and well, particularly in
Correct : C. educational applications
99. A TTL NAND gate with IIL(max) of –1.6 mA per input drives eight TTL inputs. How much current does the drive output sink?
Correct : A. –12.8 ma
100. A standard TTL circuit with a totem-pole output can sink, in the LOW state (IOL(max)),