Quiznetik

Digital Principles and System Design | Set 1

1. Any signed negative binary number is recognised by its

Correct : A. msb

2. The parameter through which 16 distinct values can be represented is known as

Correct : C. word

3. If the decimal number is a fraction then its binary equivalent is obtained by                  the number continuously by 2.

Correct : B. multiplying

4. The representation of octal number (532.2)8 in decimal is

Correct : A. (346.25)10

5. The decimal equivalent of the binary number (1011.011)2 is

Correct : A. (11.375)10

6. An important drawback of binary system is

Correct : A. it requires very large string of 1’s and 0’s to represent a decimal number

7. The decimal equivalent of the octal number (645)8 is

Correct : C. (421)10

8. The largest two digit hexadecimal number is

Correct : C. (ff)16

9. What is the addition of the binary numbers 11011011010 and 010100101?

Correct : C. 11101111111

10. Representation of hexadecimal number (6DE)H in decimal:

Correct : A. 6 * 162 + 13 * 161 + 14 * 160

11. 100101 × 0110 = ?

Correct : C. 101111110

12. Perform multiplication of the binary numbers: 01001 × 01011 = ?

Correct : A. 001100011

13. Divide the binary numbers: 111101 ÷ 1001 and find the remainder

Correct : D. 0011

14. Divide the binary number (011010000) by (0101) and find the quotient

Correct : B. 101001

15. Binary coded decimal is a combination of

Correct : C. four binary digits

16. The decimal number 10 is represented in its BCD form as

Correct : C. 00010000

17. Carry out BCD subtraction for (68) – (61) using 10’s complement method.

Correct : A. 00000111

18. When numbers, letters or words are represented by a special group of symbols, this process is called

Correct : B. encoding

19. A three digit decimal number requires                  for representation in the conventional BCD format.

Correct : C. 12 bits

20. How many bits would be required to encode decimal numbers 0 to 9999 in straight binary codes?

Correct : B. 14

21. The excess-3 code for 597 is given by

Correct : A. 100011001010

22. The decimal equivalent of the excess-3 number 110010100011.01110101 is

Correct : A. 970.42

23. In boolean algebra, the OR operation is performed by which properties?

Correct : D. all of the mentioned

24. The expression for Absorption law is given by

Correct : A. a + ab = a

25. DeMorgan’s theorem states that

Correct : A. (ab)’ = a’ + b’

26. (A + B)(A’ * B’) = ?

Correct : B. 0

27. According to boolean law: A + 1 = ?

Correct : A. 1

28. The involution of A is equal to

Correct : A. a

29. Simplify Y = AB’ + (A’ + B)C.

Correct : A. ab’ + c

30. The boolean function A + BC is a reduced form of

Correct : B. (a + b)(a + c)

31. In which of the following gates the output is 1 if and only if at least one input is 1?

Correct : D. or

32. The time required for a gate or inverter to change its state is called

Correct : C. propagation time

33. What is the minimum number of two input NAND gates used to perform the function of two input OR gates?

Correct : C. three

34. Odd parity of word can be conveniently tested by

Correct : D. xor gate

35. The number of full and half adders are required to add 16-bit number is

Correct : B. 1 half adders, 15 full adders

36. Which of the following will give the sum of full adders as output?

Correct : D. three bit counter

37. An OR gate can be imagined as

Correct : B. switches connected in parallel

38. How many full adders are required to construct an m-bit parallel adder?

Correct : C. m-1

39. Boolean Function is of the form of

Correct : A. truth values

40. The result of X+X.Y is X.

Correct : A. true

41. In the boolean function w=f(X,Y,Z), what is the RHS referred to as

Correct : B. expression

42. The general form for calculating the number of rows in a truth table is

Correct : C. 2n

43. The number of literals in the expression F=X.Y’ + Z are

Correct : B. 3

44. The complement term for X’.Y’.Z + X.Y will be

Correct : B. (x+y+z’)(x’+y’)

45. What is the complement of X’Y’Z?

Correct : C. x+y+z’

46. The minterm of any expression is denoted by

Correct : B. m

47. The min term when X=Y=Z=0 is

Correct : C. x’y’z’

48. The max term when X=Y=Z=1 is

Correct : A. x’+y’+z’

49. A product term containing all K variables of the function in either complemented or uncomplemented form is called a

Correct : A. minterm

50. The canonical sum of product form of the function y(A,B) = A + B is

Correct : B. ab + ab’ + a’b

51. A variable on its own or in its complemented form is known as a

Correct : B. literal

52. Maxterm is the sum of                      of the corresponding Minterm with its literal complemented.

Correct : A. terms

53. Canonical form is a unique way of representing

Correct : C. boolean expressions

54. There are                            Minterms for 3 variables (a, b, c).

Correct : C. 8

55. expressions can be implemented using either (1) 2-level AND-OR logic circuits or (2) 2-level NAND logic circuits.

Correct : C. sop

56. There are              cells in a 4-variable K-map.

Correct : B. 16

57. The K-map based Boolean reduction is based on the following Unifying Theorem: A + A’ = 1.

Correct : B. non impact

58. Each product term of a group, w’.x.y’ and w.y, represents the                         in that group.

Correct : C. sum-of-minterms

59. The prime implicant which has at least one element that is not present in any other implicant is known as

Correct : A. essential prime implicant

60. Product-of-Sums expressions can be implemented using

Correct : D. both 2-level or-and and nor logic circuits

61. Each group of adjacent Minterms (group size in powers of twos) corresponds to a possible product term of the given

Correct : A. function

62. Don’t care conditions can be used for simplifying Boolean expressions in

Correct : C. k-maps

63. It should be kept in mind that don’t care terms should be used along with the terms that are present in

Correct : A. minterms

64. Using the transformation method you can realize any POS realization of OR-AND with only.

Correct : D. nor

65. There are many situations in logic design in which simplification of logic expression is possible in terms of XOR and                                    operations.

Correct : A. x-nor

66. In case of XOR/XNOR simplification we have to look for the following

Correct : D. both diagonal and offset adjencies

67. Entries known as                                mapping.

Correct : A. diagonal

68. The code where all successive numbers differ from their preceding number by single bit is

Correct : D. gray

69. How many AND gates are required to realize Y = CD + EF + G?

Correct : D. 2

70. The NOR gate output will be high if the two inputs are

Correct : A. 00

71. A full adder logic circuit will have

Correct : D. three inputs and two outputs

72. How many two input AND gates and two input OR gates are required to realize Y = BD + CE + AB?

Correct : A. 3, 2

73. Which of following are known as universal gates?

Correct : A. nand & nor

74. Which of the circuits in figure (a to d) is the sum-of- products implementation of figure (e)?

Correct : D. x=a’b’+ab

75. The device shown here is most likely a

Correct : D. d

76. What type of logic circuit is represented by the figure shown below?

Correct : B. xnor

77. What is the indication of a short to ground in the output of a driving gate?

Correct : B. there is a signal loss to all load gates

78. For the device shown here, assume the D input is LOW, both S inputs are LOW and the input is LOW. What is the status of the Y’ outputs?

Correct : A. d

79. Which of the following combinations of logic gates can decode binary 1101?

Correct : B. one 4-input and gate, one inverter

80. The carry propagation can be expressed as

Correct : B. cp = a + b

81. 3 bits full adder contains

Correct : D. 8 combinational inputs

82. The basic building blocks of the arithmetic unit in a digital computers are

Correct : B. adders

83. A digital system consists of            types of circuits.

Correct : A. 2

84. In a sequential circuit, the output at any time depends only on the input values at that time.

Correct : C. both past output and present input

85. The design of an ALU is based on

Correct : B. combinational logic

86. If the two numbers are unsigned, the bit conditions of interest are the              carry and a possible             result.

Correct : D. output, zero

87. If the two numbers include a sign bit in the highest order position, the bit conditions of interest are the sign of the result, a zero indication and

Correct : C. an overflow condition

88. In parts of the processor, adders are used to calculate

Correct : D. all of the mentioned

89. Total number of inputs in a half adder is

Correct : A. 2

90. In which operation carry is obtained?

Correct : B. addition

91. If A and B are the inputs of a half adder, the carry is given by

Correct : A. a and b

92. Half-adders have a major limitation in that they cannot

Correct : C. accept a carry bit from a previous stage

93. If A, B and C are the inputs of a full adder then the carry is given by

Correct : A. a and b or (a or b) and c

94. How many AND, OR and EXOR gates are required for the configuration of full adder?

Correct : B. 2, 1, 2

95. How many outputs are required for the implementation of a subtractor?

Correct : B. 2

96. Let the input of a subtractor is A and B then what the output will be if A = B?

Correct : A. 0

97. Let A and B is the input of a subtractor then the output will be

Correct : A. a xor b

98. Let A and B is the input of a subtractor then the borrow will be

Correct : B. a’ and b

99. The full subtractor can be implemented using

Correct : B. two half subtractors and an or gate

100. The output of a subtractor is given by (if A, B and X are the inputs).

Correct : B. a xor b xor x