Boolean Algebra and Logic CircuitsCOMPUTER 1

1. A British Mathematician George Boole introduced an algebra of binary numbers in: C

a) 1845 b) 1850
c) 1854 d) 1860
2. Choose the correct statement: D
a) Boolean algebra is also known as Logical Algebra
b) Boolean algebra is also known as Switching Algebra
c) The mathematical expressions of the Boolean algebra re called Boolean expressions
d) All of the above
3. Choose the correct statement: C
a) Boolean algebra does not differ from ordinary algebra
b) Boolean algebra deals with real numbers
c) Boolean algebra has only two basic operators “+” and “.” And a complement operator
d) Boolean algebra does not have a complement operator
4. Boolean Algebra has only _______ basic operators: A
a) Two b) Three
c) Four d) Five
5. Suppose two inputs A and B are added logically to give a single output. Possible combinations for B
these variables are:
a) 2 b) 4
c) 8 d) 16
6. In Boolean Algebra: A
a) X + =1 b) X + =0
c) X + = -1 d) None of these
7. In Boolean Algebra: C
a) X . =1 b) X . = -1
c) X . =0 d) None of these
8. In Boolean Algebra, for X = 0, =? A
a) X b) 1
c) 0 d) None of these
9. In Boolean algebra for X = 1, =? C
a) 0 b) 1
c) X d) None of these
10. In Boolean algebra for X + ( . Y) = ? C
a) X b) Y
c) X . Y d) X + Y
11. In Boolean algebra for X . ( + Y) = ?
a) X b)
c) X . Y d) X + Y
12. In Boolean Algebra =? D
a) + b) X . Y
c) . d) .
13. In Boolean algebra =? C
a) + b) .
c) + d)
14. Choose the incorrect statement: A
a) A Boolean expression is evaluated from right to left
b) The expression enclosed in the parenthesis is evaluated first
c) Fist of all the complement operation is performed
d) The OR operations (+) are evaluated in the end
15. In Boolean algebra (X +Y) . (X + Z) = ? A
a) X + Y . Z b) X . X + Y . Z
c) X . Z + Y d) X . Y + Z
 Boolean Algebra and Logic CircuitsCOMPUTER 2

16. Suppose there are three inputs A, B and C. For three inputs, the maximum: C
a) 3 b) 4
c) 8 d) 27
17. Single NOR-gate can perform all functions of: D
a) OR gate b) AND gate
c) NOT gate d) All of these
18. Choose the correct statement: A
a) In a NAND gate if all the inputs are 1, the output will be 0
b) In a NAND gate if all the inputs are 1, the output will be 1
c) Both ‘a’ and ‘b’ d) Neither ‘a’ nor ‘b’
19. The symbol is used to present a _______ operation: D
a) OR b) AND
c) NOT d) NAND
20. The XOR gate is also known as: A
a) The exclusive OR-gate b) The OR-gate
c) The AND-gate d) The NOR-gate
21. Choose the correct statement: B
a) The XOR gate gets more than one input signals and if inputs are different, the output will be 0
b) The XOR gate gets more than one input signals and if inputs are different, the output will be 1
c) The XOR gate gets more than one input signals and if inputs are same, the output will be 1
d) None of these
22. The XNOR gate is also known as: B
a) The NOR-gate b) The exclusive NOR-gate
c) The AND-gate d) The OR-gate
23. Choose the correct statement: A
a) The XNOR gate gets more than one input signals and gives a single output. If all are same, the
output will be ‘1’
b) The XNOR gate gets more than one input signals and gives a single output. If all are same, the
output will be ‘0’
c) The XNOR gate gets more than one input signals and gives a single output. If all are different,
the output will be ‘1’
d) None of these
24. Choose the correct statement: B
a) The XOR gate gets more than one input signals and if inputs are same, the output will be ‘1’
b) The XOR gate gets more than one input signals and if inputs are same, the output will be ‘0’
c) The XOR gate gets more than one input signals and if inputs are different, the output will be ‘1’
d) None of these
25. Choose the correct statement: A
a) The XNOR gate gets more than one input signals and gives a single output. If inputs are
different, the output will be ‘0’
b) The XNOR gate gets more than one input signals and gives a single output. If inputs are
different, the output will be ‘1’
c) The XNOR gate gets more than one input signals and gives a single output. If inputs are
same, the output will be ‘0’
d) None of these
26. In Boolean algebra (X + Y) . (X + ) = ? A
a) X b)
c) +Y d)
27. In Boolean algebra =? B
a) X b)
c) +Y d)
28. In Boolean algebra A . C + A . B + +B=? B
a) A . B + b) A . B +
c) B . C + d) A . C + B
 Boolean Algebra and Logic CircuitsCOMPUTER 3

29. In Boolean algebra + D

a) A . B + b) .B+A.B
c) A . B + A . B d) .B+A.
30. Choose the correct statement: A
a) F1 = F2 = F3 if
i) F1 = X. . + X. . Z + X. Y. + X. Y. Z
ii) F2 = (X + Y + ) . X
iii) F3 = X
b) F1 = F2 = F3 if
i) F1 = . . +X .Y.Z
ii) F2 = (X + Y. ) . X
iii) F3 = X
c) F1 = F2 = F3 if
i) F1 = X. . + X . . Z + X. Y. + X. Y. Z
ii) F2 = (X + Y . Z) . X
iii) F3 = X
d) F1 = F2 = F3 if
i) F1 = + X. Y. Z
ii) F2 = (X + Y. ) . X
iii) F3 = X
31. In Boolean algebra C
a) A . B b)
c) A + B d) None of these
32. One of the advantages of simplifying the Boolean function is: A
a) Both the original function and the simplified function give the same output
b) The simplified function uses greater number of logic gates
c) Because greater logic gates are used, the production cost is reduced
d) Because of greater logic gates, the logic circuit becomes fast in operations
33. Using Boolean theorems and axioms, the function: F = A + AB + + AA can be simplified as: B
a) b) A
c) B d)
34. Using K-map, the function: F = A + AB + + AA can be simplified as: C
a) B b)
c) A d)
35. There are _______ types of adders: A
a) Two b) Three
c) Four d) Five
36. In parallel binary adders full adders are connected in: B
a) Series b) Parallel
c) Both series and parallel d) Neither series nor parallel
37. Full adders are the electronic circuits that take _______ input bits: B
a) Two b) Three
c) Four d) Five
38. Subtractors are of _______ types: A
a) Two b) Three
c) Four d) Five
39. Half subtractors are the electronic circuits that take _______ binary inputs: A
a) Two b) Three
c) Four d) Five
 Boolean Algebra and Logic CircuitsCOMPUTER 4

40. A half subtractor has _______ outputs: A

a) Two b) Three
c) Four d) Five
41. Full subtractors are the electronic circuits that take _______ input bits: B
a) Two b) Three
c) Four d) Five
42. Fabrication of a logic circuit has to be preceded by _______ crucial design stages: A
a) Two b) Three
c) Four d) Five
43. In Boolean algebra: B
( . b. + a . b. ) + (a. b. c + a. .c) = ?
a) b. c + a. c b) b . + a . c
c) . B + a. c d) a. b + . C
44. In Boolean algebra: B
( . . + . . ) + (a. . + a. .c) = ?
a) b b)
c) a d)
45. In Boolean algebra: D
(a. . + . . ) + (a. . + . .c) = ?
a) a b)
c) b d)
46. Boolean algebra is: D
a) used for arithmetical operation is ALU b) an aid for binary conversion
c) useful for error detection and error correction
d) used to describe the behavior and structure of logic networks and as an aid in the design of logic
system
47. Boolean algebra is also known as: C
a) logical algebra b) control algebra
c) switching algebra d) programming algebra
48. Boolean algebra uses which of the following to represent arithmetic quantities: C
a) decimal digits b) exponents
c) binary bits d) fractions
49. Which of the following operations are used by Boolean algebra? D
a) Boolean addition b) Boolean multiplication
c) Boolean complementation d) All of the above
50. Logical addition refers to operation of: A
a) OR gate b) AND gate
c) NOT gate d) inverter gate
51. Logical multiplication refers to operation of: B
a) OR gate b) AND gate
c) NOT gate d) inverter gate
52. The output will be one in case any input is one in the case of: A
a) OR gate b) AND gate
c) NAND gate d) NOT gate
53. Which of the following gate is two-level logic gate: C
a) OR gate b) AND gate
c) EXCLUSIVE OR gate d) NAND gate
54. The logic device that perform Boolean multiplication is: A
a) AND gate b) OR gate
c) inverter d) none of these
55. The logic device that perform Boolean addition is: B
a) AND gate b) OR gate
c) inverter d) none of these
 Boolean Algebra and Logic CircuitsCOMPUTER 5

56. Which of the following statement is true in the case of AND gate with input A and B: C
a) if A and B are applied, there will not be any output
b) if neither input is applied, there will be an output
c) if one input is applied there will not be any output
d) if one input is applied there will be an output
57. Which of the following function is referred as the complementary? B
a) OR function b) NOT function
c) NAND function d) AND function
58. An OR gate has 6 input. The number of input words in its truth table are: C
a) 6 b) 32
c) 64 d) 128
59. An AND gate will function as OR if: D
a) all the inputs to the gates are “1” b) all the inputs are “0”
c) a NOT gate is added to it d) all the inputs and outputs are complemented
60. Odd parity of a word can be conveniently tested by: B
a) OR gate b) XOR gate
c) NOR gate d) NAND gate
61. NAND gates are preferred over others because these: C
a) have lower fabrication area b) can be used to make any gate
c) consume least electronic power d) provide maximum density in a chip
62. According to DeMorgan’s theorem = C
a) + + + b) +
c) d) A + B + C + D
63. According to DeMorgan’s theorem = B
a) b) + + +
c) + d)
64. Boolean description for the exclusive OR gate for two inputs x and y can be written as: C
a) + b) .
c) x . + . y d) x . y + .
65. Boolean expression for NOR gate with two inputs x and y can be written as: A
a) b)
c) + d) x . + . y
66. Boolean expression for NAND gate with two inputs x and y cane be written as: A
a) b) .
c) d) x . + . y
67. If A and B are two 1-bit numbers, what logic gates will be required to test for A = B? C
a) NOR gate b) EXCLUSIVE OR gate
c) EXCLUSIVE NOT gate d) OR gate
68. According to DeMOrgan’s law = B
a) x + y b) +
c) . d)
69. According to DeMorgan’s law = A
a) . b) x + y
c) + d)
70. The commutative law in Boolean Algebra, where a, b and c are binary numbers is: C
a) a + 0 = a b) a + 1 = 1
c) a + b = b + a d) a . (b + c) = a . b + a . c
71. According to absorption law x + x . y = A
a) x b) y
c) 1 + x d) 1 + y
72. According to absorption law x . (x + y) = A
a) x b) y
c) 1 + x d) 1 + y
 Boolean Algebra and Logic CircuitsCOMPUTER 6

73. According to Boolean algebra A+A+….+A is: A

a) A b) n A
c) 0 d) 1
74. In Boolean algebra A. A. A. A. A. = B
a) 5A b) A
c) A5 d) 1
75. In Boolean algebra A.0 is: A
a) 0 b) 1
c) A + 0 d) A + 1
76. The Boolean Algebra is based on the premise that: C
a) there are two states
b) differential equations can be solved by analog circuits
c) either a statement is true or false d) arithmetic operations can be carried out
77. The circuit that is used for parallel to serial conversion is: C
a) decoder b) encoder
c) multiplexer d) de multiplexer
78. The heart of analog to digital converter (ADC): A
a) comparator b) pulse generator
c) voltage source d) current source
79. The half adder circuit has: B
a) one input b) two inputs
c) three inputs d) always more than two inputs
80. The number of inputs to full adder are: C
a) 1 b) 2
c) 3 d) 4
81. In a three input NAND gate, if all the inputs are 1, the output is: A
a) 0 b) 1
c) 3 d) indeterminate
82. In a three input AND gate all but one inputs are 1, the output is: A
a) 0 b) 1
c) 3 d) indeterminate
83. According to Idempotent law, x + x = _______ C
a) 1 b) 0
c) x d) x . x
84. According to Idempotent law x . x = _______ C
a) 1 b) 0
c) x d) x . x
85. According to Boolean algebra x + = _______ B
a) 0 b) 1
c) x d)
86. According to Boolean algebra x . = _______ A
a) 0 b) 1
c) x d)
87. According to Boolean algebra x + 1 = _______
a) 0 b) 1
c) x d)
88. In a half adder circuit, if x and y be input then output S (sum) and C (carry over) will be: A
a) S = . y + x . , C = x . y b) S = x + y, C =1
c) S = x.y + . , C = . d) S = x.y, C = 1
89. Pick up wrong logical expression: D
a) 1 0=0 1=1 b) 0 0=1 1=0
c) =X Y d) X X=1
 Boolean Algebra and Logic CircuitsCOMPUTER 7

90. Transistors characterized a major improvement over

a) semiconductors b) disk packs
c) vacuum tubes d) integrated circuit C
91. Silicon chips of integrated circuit (ICs) marked the advent of the
a) second generation b) fourth generation
c) third generation d) fifth generation C
92. The fourth generation is identified by the
a) microcomputer b) introduction of ICs
c) IBM System /360 d) Microprocessor D
93. Desktop and personal computers are other names or
a) micro computers b) mini computers
c) mainframes d) peripheral equipment A
94. A bar code reader is an example of a(n)
a) processing device b) storage device
c) input device d) output device C
95. Printers and screens are common forms of
a) input units b) output units
c) storage units d) processing units B
96. An examples of peripheral equipment:
a) CPU b) spreadsheet
c) printer d) microcomputer C
97. A device that inputs data by scanning letters and numbers is a
a) keyboard b) wand reader
c) mouse d) diskette B
98. Another name for memory is
a) secondary storage b) disk storage
c) primary storage d) tape storage C
99. Which is not computer classification?
a) maxi computer b) mini computer
c) micro computer d) mainframe A
100. An input device that translate motions of a ball rolled on a flat surface to the screen is the
a) wand reader b) keyboard
c) barcode reader d) mouse D
101. Laser beam technology is used for
a) terminals b) optical disk
c) keyboards d) magnetic tape B
102. Integrated circuits, solid state technology was used in following generation of computers: C
a) first b) second
c) third d) fourth
103. An AND gate will function as OR is: D
a) all the inputs to the gates are ‘1’ b) all the inputs are ‘0’
c) either of the input is ‘1’ d) all the inputs and outputs are
complemented
104. Which of the following IC logic family has maximum fan out capacity? D
a) TTL b) DTL
c) MOS d) CMOS
105. How many input lead will be required for a chip containing four two-input NOT gates? B
a) 7 b) 14
c) 12 d) 13
106. The half adder circuit has: B
a) one input b) two inputs
c) three inputs d) no inputs
107. Which of the following is the example of sequential circuit: D
a) counter b) shift register
c) accumulator d) all of the above
 Boolean Algebra and Logic CircuitsCOMPUTER 8

108. Popular applications of flip-flop are: D

a) counters b) shift registers
c) transfer registers d) all of these
109. The number of inputs to full adder are: C
a) 1 b) 2
c) 3 d) 4
110. Boolean description for the exclusive OR gate for two inputs X and Y can be written as: C
a) + b) .
c) X . + . Y d) X . + . Y
111. The hamming code is used in the digital computer to: A
a) detect the error b) correct the error
c) analyze the error d) either detect or correct the error
112. The Boolean Algebra is based on the premise that: C
a) there are two states b) data can be stored and retrieved
c) either a statement is true or false d) arithmetic operations can be carried out
113. In Boolean algebra A.A.A.A.A D
a) 5 A b) A/5
c) A5 d) A
114. In Boolean algebra A.0 is B
a) 1 b) 0
c) A d) 1 + 4
115. According to Idempotent law, x + x = ? C
a) 1 b) 0
c) x d) x.x
116. According to Idempotent law, x.x = ? C
a) 1 b) 0
c) x d) x + x
117. According to complementary nature of Boolean algebra, x + x = B
a) b)
c) x d) x x
118. According to complementary nature of Boolean algebra, x . x = A
a) b)
c) x d) x x
119. The output will be one in case any input is one is the case of: A
a) OR gate b) AND gate
c) NAND gate d) NOT gate
120. The binary addition, (1 + 1) will result in: D
a) 0 b) 1
c) 0 with no carry d) 0 with 1 carry
121. Which of the following circuit is known as half adder: D
a) EXCLUSIVE AND circuit b) Flip-flop circuit
c) INCLUSIVE OR circuit d) EXCLUSIVE OR circuit
122. Which of the following function is referred as the complementary? B
a) OR function b) NOT function
c) NAND function d) AND function
123. A flip-flop is a: B
a) monostable device b) bistable device
c) astable device d) oscillatory device
124. NAND gates are preferred over others because these: C
a) have lower fabrication area b) can be used to make any gate
c) consume least electric power d) provide maximum density in a chip
125. For which of the following flip-flops the output is clearly defined for all combinations of two inputs? C
a) D-type flip-flop b) R-S flip-flop
c) J-K flip-flop d) T flip-flop
 Boolean Algebra and Logic CircuitsCOMPUTER 9

126. It is difficult to design asynchronous sequential circuit because: D

a) external clock is to be provided b) it is more complex
c) memory required is enormous d) generally they involve stability problem
127. A simple flip-flop: B
a) is 2 bit memory b) is 1 bit memory
c) is a four-state device d) has nothing to do with memory
128. A 4-bit shift register can be made by using: B
a) 3 JK flip-flop b) 4 JK flip-flop
c) 5 JK flip-flop d) 8 JK flip-flop
129. The main difference between JK and RS flip-flop is that: C
a) JK flip-flop does not need a clock pulse b) there is a feedback in JK flip-flop
c) JK flip-flop accepts both inputs as 1 d) JK flip-flop is acronym of junction cathode
multi-vibrator
130. Boolean algebra is: D
a) used for arithmetical operation in ALU b) an aid for binary conversion
c) useful for programming languages
d) is used to describe the behaviour and structure of logic networks and as an aid in the design of
logic system
131. Boolean algebra is also known as: C
a) logical algebra b) code algebra
c) switching algebra d) control algebra
132. In binary coded decimal (BCD) format, each decimal digit is encoded by: B
a) 3 bits b) 4 bits
c) 6 bits d) 7 bits
133. The race condition is related to: C
a) sequential circuits b) digital circuits
c) asynchronous circuits d) synchronous circuits
134. Which of the following semiconductor memory utilizes both p-and n-channel devices on the same D
substrate:
a) bipolar b) static MOS
c) dynamic MOS d) CMOS
135. A parallel adder when compared with serial adder: A
a) is faster b) is slower
c) work at same speed d) is less complex
136. Which of the following IC unit has only one output? B
a) demultiplexer b) multiplexer
c) decoder d) encoder
Boolean Algebra and Logic CircuitsCOMPUTER 10

01. Addition and subtraction are logical operations. F

02. In a Karnaugh map, adjacent cells are those that differ by one variable. F

03. A decoder is used to add binary numbers. F

04. A decoder is used to control the flow of data. F

05. A half-adder adds without carry. T

06. A half-adder can be implemented using NAND gates only. T

07. A full adder circuit can be constructed using XOR gates. T

08. A minterm is the minimum term for a Boolean function. F

09. A min term is a square of Karnaugh map. T

11. Boolean equation describe the operation of a logic circuit. T

12. Boolean expression can be used in troubleshooting. T

13. Boolean expression can be used to design logic circuits. T

14. A Boolean variable can assume the TRUE value only. F

15. A Boolean variable can assume the FALSE value only. F

16. Logic gates are the building blocks for all digital circuits. T

17. An expression formed with relational operators is called a Boolean expression. F

18. OR logic is used when both the conditions must be true. F

19. OR logic is used when one or the other condition must be true. T

20. Any digital system can be fabricated by the use of just two gates AND and OR gates. F

21. Any digital system can be fabricated by the use of just two gates OR and NOT gates. F

22. A Boolean variable can assume the TRUE or FALSE values only. T

23. An exclusive OR gate has inputs of 0 and 1. The output will be 0. F

24. An exclusive OR gate has inputs of 0 and 1. The output will be 1. T

25. The NAND gate is known as a universal gate. T

26. In Boolean algebra the value of A + B + C + 1 depends upon the values of A, B and C. F

27. A gate is logic circuit with only one output signal. T

28. In NOR gate all inputs must be low to get low output. F

29. 2’s complement is the number obtained by taking 1’s complement and then adding 1. T
Boolean Algebra and Logic CircuitsCOMPUTER 11

30. 2’s complement is the number obtained by taking 1’s complement and then subtracting 1.
F

31. The double complement of a Boolean variable equals the variable itself.T

32. An inverter is a gate with only one input. T

33. An inverter is a gate with only one output. T

34. De Morgan’s first theorem is that the complement of a sum equals the product of the complement.
T

35. De Morgan’s first theorem is that the complement of a sum equals the product of the sums.
F

36. In Boolean algebra a variable can be either a ‘0’ or a ‘1’. T

37. A truth table shows only the input possibilities for a logic circuit. F

38. A truth table shows only the output possibilities for a logic circuit. F

39. A truth table shows both the input as well as output possibilities for a logic circuit. T

40. A gate is a logical circuit which operates on one or more input signals to produce an output signal.
T

41. The output of an inverter gate is always in the opposite state from the input. T

42. The output of an investor gate is always complement f the input. T

43. OR logic gate is similar to the function of two parallel switches. T

44. The expression F = + B can be simplified as F = . F

45. AND logic gate is similar to the function of two parallel switches. F

46. Using Boolean algebra the expression F = A CD + ABCD can be simplified as F = BCD.
F

47. The operation of subtraction in Boolean algebra is valid. F

48. The operation of subtraction in Boolean algebra can be made valid. F

49. The operation of subtraction in Boolean algebra is not valid. T

50. To subtract a number B from another A, the operation required is: add B and 2’s complement of
A. F

51. To subtract a number B from another A, the operation required is: add A and 2’s complement of
B. T

52. A NAND gate with input signals inverted performs the logical AND functions. F