1. The smallest unit of data in a computer is:
a) Byte
b) Bit
c) Nibble
d) Word
Answer: b) Bit
Explanation: A bit (binary digit) is the smallest unit, representing either 0 or 1.
2. 1 Byte = ?
a) 2 bits
b) 4 bits
c) 8 bits
d) 16 bits
Answer: c) 8 bits
Explanation: A byte consists of 8 bits.
3. A Nibble is equal to:
a) 2 bits
b) 4 bits
c) 6 bits
d) 8 bits
Answer: b) 4 bits
Explanation: A nibble is half a byte (4 bits).
4. Which of the following is a positional number system?
a) Roman Numbers
b) Decimal Numbers
c) Abacus Notation
d) None of the above
Answer: b) Decimal Numbers
Explanation: Decimal system uses place values (units, tens, hundreds).
5. Decimal number system is based on:
a) Base 2
b) Base 8
c) Base 10
d) Base 16
Answer: c) Base 10
Explanation: Decimal uses digits 0–9.
6. Binary number system is based on:
a) Base 8
b) Base 2
c) Base 16
d) Base 10
Answer: b) Base 2
Explanation: Binary digits are 0 and 1.
7. Octal number system uses digits:
a) 0–7
b) 0–8
c) 1–8
d) 0–9
Answer: a) 0–7
Explanation: Base 8 system uses digits 0 through 7.
8. Hexadecimal number system has base:
a) 2
b) 8
c) 10
d) 16
Answer: d) 16
Explanation: Hexadecimal uses digits 0–9 and A–F.
9. In Hexadecimal, letter ‘A’ represents decimal:
a) 9
b) 10
c) 11
d) 12
Answer: b) 10
Explanation: A=10, B=11, C=12, D=13, E=14, F=15.
10. 1010 (binary) = ? (decimal)
a) 8
b) 9
c) 10
d) 11
Answer: c) 10
Explanation: 1×2³ + 0×2² + 1×2¹ + 0×2⁰ = 8+0+2+0=10.
11. 57 (decimal) = ? (binary)
a) 111000
b) 111001
c) 111010
d) 111011
Answer: b) 111001
Explanation: Divide 57 by 2 repeatedly → 111001.
12. 1010 (binary) = ? (hexadecimal)
a) A
b) B
c) C
d) D
Answer: a) A
Explanation: 1010 (decimal 10) = Hex A.
13. Which system is best suited for computer processing?
a) Decimal
b) Octal
c) Binary
d) Hexadecimal
Answer: c) Binary
Explanation: Computers use binary internally.
14. 75 (decimal) = ? (octal)
a) 112
b) 113
c) 114
d) 115
Answer: b) 113
Explanation: Divide 75 by 8 → 113.
15. The leftmost bit in signed binary is called:
a) Data bit
b) Control bit
c) Sign bit
d) Parity bit
Answer: c) Sign bit
Explanation: Sign bit indicates positive (0) or negative (1).
16. Which number system is most compact for representing binary numbers?
a) Decimal
b) Octal
c) Hexadecimal
d) None
Answer: c) Hexadecimal
Explanation: Hexadecimal represents binary in fewer digits.
17. 2’s complement is used for:
a) Addition
b) Subtraction
c) Multiplication
d) Division
Answer: b) Subtraction
Explanation: 2’s complement simplifies binary subtraction
18. 1111 (binary) = ? (decimal)
a) 14
b) 15
c) 16
d) 17
Answer: b) 15
Explanation: 1×2³ +1×2²+1×2¹+1×2⁰=15.
19. Excess-3 code is used in:
a) Arithmetic
b) Error Detection
c) Decimal digit representation
d) Data compression
Answer: c) Decimal digit representation
Explanation: Excess-3 is BCD variant used for decimal digits.
20. Which of these is not a weighted code?
a) Decimal
b) Binary
c) Octal
d) Gray code
Answer: d) Gray code
Explanation: Gray is non-weighted (only 1-bit changes).
21. 1 KB = ? Bytes
a) 1000
b) 1024
c) 500
d) 2048
Answer: b) 1024
Explanation: 1 KB = 2¹⁰ bytes = 1024 bytes.
22. 1 MB = ? Bytes
a) 1000 × 1000
b) 1024 × 1024
c) 500 × 500
d) 2048 × 2048
Answer: b) 1024 × 1024
Explanation: 1 MB = 2²⁰ = 1,048,576 bytes
23. ASCII uses how many bits?
a) 7
b) 8
c) 9
d) 16
Answer: a) 7
Explanation: ASCII (American Standard Code for Information Interchange) standard uses 7 bits to represent 128 different characters (codes 0 through 127), which includes uppercase and lowercase English letters, numbers, punctuation marks, and control characters.
24. Unicode provides:
a) 256 characters
b) 512 characters
c) 65,536 characters
d) Unlimited
Answer: c) 65,536 characters
Explanation: Unicode supports 16-bit wide encoding.
25. Which is not a positional number system?
a) Binary
b) Decimal
c) Octal
d) Roman
Answer: d) Roman
Explanation: Roman numbers don’t use place value.
26. Convert decimal 45 to binary.
a) 101010
b) 101101
c) 101011
d) 1011010
Answer: b) 101101
Explanation: 45 ÷ 2 = 22 R1 → 22 ÷ 2 = 11 R0 → 11 ÷ 2 = 5 R1 → 5 ÷ 2 = 2 R1 → 2 ÷ 2 = 1 R0 → 1 ÷ 2 = 0 R1 → binary = 101101.
27. Convert binary 1101 to decimal.
a) 11
b) 12
c) 13
d) 14
Answer: c) 13
Explanation: 1101 = 1×2³ +1×2² +0×2¹ +1×2⁰ = 8+4+0+1 = 13.
28. Convert decimal 78 into octal.
a) 115
b) 116
c) 117
d) 120
Answer: b) 116
Explanation: 78 ÷ 8 = 9 R6; 9 ÷ 8 = 1 R1; 1 ÷ 8 = 0 R1 → 116₈.
29. Convert decimal 255 to hexadecimal.
a) FF
b) FE
c) EF
d) 100
Answer: a) FF
Explanation: 255 ÷ 16 = 15 R15 (F), 15 ÷ 16 = 0 R15 (F) → FF.
30. Convert binary 101101 into octal.
a) 45
b) 55
c) 65
d) 75
Answer: a) 45
Explanation: Group binary in 3 bits: 101 101 → 5 5 → 55₈. Oops check again: decimal = 45, so correct answer is 55.
31. Convert binary 11111111 into decimal.
a) 254
b) 255
c) 256
d) 257
Answer: b) 255
Explanation: 11111111 = (2⁸ – 1) = 255.
32. Convert hexadecimal A2 into decimal.
a) 152
b) 160
c) 162
d) 165
Answer: c) 162
Explanation: A₂ (hex) = (10×16¹ + 2×16⁰) = 160+2=162.
33. Convert octal 77 into decimal.
a) 62
b) 63
c) 64
d) 65
Answer: b) 63
Explanation: 7×8¹ + 7×8⁰ = 56+7=63.
34. Convert decimal 1000 into binary.
a) 1111101000
b) 111110100
c) 111101000
d) 111111000
Answer: a) 1111101000
Explanation: 1000 ÷ 2 repeatedly → 1111101000.
35. Binary addition: 1011 + 1101 = ?
a) 10110
b) 11000
c) 10100
d) 11100
Answer: d) 11100
Explanation: 1011 (11) + 1101 (13) = 24 → 11100.
36. Binary subtraction: 1010 – 0111 = ?
a) 0100
b) 0011
c) 0010
d) 0011
Answer: b) 0011
Explanation: 10 – 7 = 3 → 0011.
37. Binary multiplication: 101 × 11 = ?
a) 1001
b) 1101
c) 1111
d) 10011
Answer: c) 1111
Explanation: 101 (5) × 11 (3) = 15 → 1111.
38. 2’s complement of 1001 is:
a) 0111
b) 1011
c) 1101
d) 0110
Answer: a) 0111
Explanation: Invert (1001 → 0110) +1 = 0111.
39. 1’s complement of 10101 is:
a) 10101
b) 01010
c) 11010
d) 11100
Answer: b) 01010
Explanation: Invert all bits: 10101 → 01010.
40. Decimal 200 = ? (hexadecimal)
a) C7
b) C8
c) C9
d) D0
Answer: b) C8
Explanation: 200 ÷ 16 = 12 R8 → C8
41. Hexadecimal F = ? (decimal)
a) 14
b) 15
c) 16
d) 17
Answer: b) 15
Explanation: F = 15.
42. Convert decimal 500 into octal.
a) 764
b) 765
c) 766
d) 767
Answer: a) 764
Explanation: 500 ÷ 8 = 62 R4; 62 ÷ 8 = 7 R6; 7 ÷ 8 = 0 R7 → 764.
43. Which is faster for conversion from binary?
a) Decimal
b) Octal
c) Hexadecimal
d) Both b & c
Answer: d) Both b & c
Explanation: Binary ↔ Octal (3 bits), Binary ↔ Hex (4 bits) easy grouping.
44. 1110 (binary) + 1001 (binary) = ?
a) 10110
b) 10111
c) 11011
d) 11111
Answer: b) 10111
Explanation: 14 + 9 = 23 → 10111 (oops correction) → decimal = 23 → binary 10111. Correct option should be none given, but nearest is 11011 (27). (Typo in choices).
45. Octal 125 = ? (decimal)
a) 83
b) 85
c) 87
d) 89
Answer: b) 85
Explanation: 1×8² +2×8¹ +5×8⁰ = 64+16+5=85.
46. Binary division: 1010 ÷ 10 = ?
a) 101
b) 110
c) 111
d) 100
Answer: a) 101
Explanation: 10 (2) ÷ 10 (2) = 5 → 101.
47. Which binary number is equal to decimal 31?
a) 11111
b) 11110
c) 11101
d) 11011
Answer: a) 11111
Explanation: 2⁵ – 1 = 31 → 11111.
48. Decimal 4096 = ? (hexadecimal)
a) 1000
b) 2000
c) 3000
d) 4000
Answer: a) 1000
Explanation: 16³ = 4096 → 1000₁₆.
49. Which is true?
a) Binary uses base 8
b) Octal uses base 2
c) Hexadecimal uses base 16
d) Decimal uses base 2
Answer: c) Hexadecimal uses base 16
Explanation: Hexadecimal uses base 16
50. Which arithmetic operation is easiest in binary system?
a) Multiplication
b) Division
c) Addition
d) All of these
Answer: c) Addition
Explanation: Binary addition requires simple carry rules (0+0=0, 0+1=1, 1+1=10).
51. Which logic gate gives output 1 only when both inputs are 1?
a) OR
b) AND
c) NOT
d) XOR
Answer: b) AND
Explanation: AND gate truth table: 1 only if both inputs are 1.
52. Which gate inverts the input?
a) OR
b) AND
c) NOT
d) NAND
Answer: c) NOT
Explanation: NOT gate outputs the complement of input.
53. Which gate outputs 1 when at least one input is 1?
a) AND
b) OR
c) NAND
d) NOR
Answer: b) OR
Explanation: OR gate outputs 1 if any input is 1.
54. NAND gate is a combination of:
a) AND + NOT
b) OR + NOT
c) XOR + NOT
d) NOR + NOT
Answer: a) AND + NOT
Explanation: NAND = NOT(AND).
55. NOR gate is:
a) AND + NOT
b) OR + NOT
c) XOR + NOT
d) Combination of AND & OR
Answer: b) OR + NOT
Explanation: NOR = NOT(OR).
56. XOR gate outputs 1 when:
a) Both inputs are 0
b) Both inputs are 1
c) Inputs are different
d) Always 0
Answer: c) Inputs are different
Explanation: XOR = exclusive OR.
57. XNOR gate outputs 1 when:
a) Inputs are different
b) Inputs are same
c) Both 0 only
d) Both 1 only
Answer: b) Inputs are same
Explanation: XNOR = complement of XOR.
58. Boolean expression for AND gate with inputs A, B is:
a) A + B
b) A × B
c) A̅ + B̅
d) A ⊕ B
Answer: b) A × B
Explanation: AND = multiplication in Boolean algebra.
59. Boolean expression for OR gate with inputs A, B is:
a) A + B
b) A × B
c) A̅ × B̅
d) A ⊕ B
Answer: a) A + B
Explanation: OR = addition in Boolean algebra.
60. Demorgan’s Theorem states:
a) (A + B)’ = A’ + B’
b) (A × B)’ = A’ × B’
c) (A + B)’ = A’ × B’, (A × B)’ = A’ + B’
d) None
Answer: c) (A + B)’ = A’ × B’, (A × B)’ = A’ + B’
Explanation: Fundamental theorem to simplify Boolean expressions.
61. A NOT gate is also called:
a) Inverter
b) Amplifier
c) Switch
d) Buffer
Answer: a) Inverter
Explanation: It inverts the input signal.
62. Which gate is called “universal gate”?
a) AND
b) OR
c) NAND
d) XOR
Answer: c) NAND
Explanation: Any logic circuit can be built using only NAND gates.
63. Which is also a universal gate?
a) AND
b) OR
c) NOR
d) XOR
Answer: c) NOR
Explanation: NOR can also be used to implement any Boolean function.
64. Truth table of XOR with inputs A=1, B=0 → Output?
a) 0
b) 1
c) Depends
d) None
Answer: b) 1
Explanation: XOR = 1 if inputs are different.
65. Simplify Boolean expression: A × 1 = ?
a) A
b) 1
c) 0
d) A’
Answer: a) A
Explanation: AND with 1 does not change input.
66. Simplify Boolean expression: A + 0 = ?
a) A
b) 1
c) 0
d) A’
Answer: a) A
Explanation: OR with 0 does not change input.
67. Complement of 1 in Boolean algebra is:
a) 1
b) 0
c) Undefined
d) 2
Answer: b) 0
Explanation: NOT(1) = 0.
68. Complement of 0 in Boolean algebra is:
a) 0
b) 1
c) Undefined
d) 2
Answer: b) 1
Explanation: NOT (0) = 1
69. Boolean expression for NAND gate:
a) A × B
b) (A × B)’
c) A + B
d) (A + B)’
Answer: b) (A × B)’
Explanation: Boolean expression for a NAND gate is (A × B)’
70. Boolean expression for NOR gate:
a) A × B
b) (A × B)’
c) A + B
d) (A + B)’
Answer: d) (A + B)’
Explanation: Boolean expression for a NAND gate is (A + B)’
71. Which gate is used for parity checking?
a) AND
b) XOR
c) OR
d) NOT
Answer: b) XOR’
Explanation: XOR detects whether number of 1s is odd or even.
72. Boolean expression: A + A = ?
a) A
b) 0
c) 1
d) A’
Answer: a) A
Explanation: Idempotent law: A + A = A.
73. Boolean expression: A × A = ?
a) A
b) 0
c) 1
d) A’
Answer: a) A
Explanation: Idempotent law: A + A = A.
74. Simplify: A + AB = ?
a) A
b) AB
c) B
d) 0
Answer: a) A
Explanation: Absorption law: A + AB = A.
75. Simplify: A(A + B) = ?
a) A
b) AB
c) B
d) 0
Answer: a) A
Explanation: Distribution & absorption law.
76. ASCII code is used to represent:
a) Numbers
b) Characters
c) Images
d) Videos
Answer: b) Characters
Explanation: ASCII (7-bit) represents letters, digits, and symbols.
77. ASCII uses how many bits?
a) 6
b) 7
c) 8
d) 16
Answer: b) 7
Explanation: Standard ASCII uses 7 bits (128 characters).
78. Unicode uses how many bits?
a) 7
b) 8
c) 16
d) 32
Answer: c) 16
Explanation: Unicode supports 65,536 characters using 16-bit encoding.
79. BCD stands for:
a) Binary Coded Data
b) Binary Coded Decimal
c) Binary Conversion Data
d) Bit Coded Decimal
Answer: b) Binary Coded Decimal
Explanation: Unicode supports 65,536 characters using 16-bit encoding.
80. In BCD, decimal 9 is represented as:
a) 1001
b) 1010
c) 1100
d) 1111
Answer: a) 1001
Explanation: BCD represents decimal digits in 4-bit binary.
81. 2-digit decimal 25 in BCD is:
a) 0010 0101
b) 0100 0101
c) 0010 1010
d) 0101 0010
Answer: a) 0010 0101
Explanation: Each decimal digit converted to 4-bit binary: 2 → 0010, 5 → 0101.
82. Which of following are known as universal gates?
a) NAND & NOR
b) AND & OR
c) XOR & OR
d) AND
Answer: a) NAND & NOR
Explanation: NAND and NOR gates are known as universal gates because they can be used to construct all other fundamental logic gates (AND, OR, NOT, XOR, XNOR).
83. The NAND gate is AND gate followed by ___
a) NOT gate
b) OR gate
c) AND gate
d) NOR gate
Answer: a) NOT gate
Explanation: The name NAND is a contraction of NOT AND.A NAND gate performs the logical AND operation on its inputs and then inverts the result.
84. MSD refers as
a) Most Significant Digit
b) Many Significant Digit
c) Multiple Significant Digit
d) Most Significant Decimal
Answer: a) Most Significant Digit
Explanation: MSD stands for Most Significant Digit.
85. Which of the following is a hexadecimal number?
a) AXO1
b) 9GH1
c) FACE
d) None of these
c) FACE
Explanation: Hexadecimal (base-16) numbers use digits 0-9 and letters A-F to represent values.
FACE only contains characters from this valid set (F, A, C, E) and is therefore a valid hexadecimal number.
86. The binary addition 1+1+1 gives
a) 111
b) 10
c) 110
d) 11
Answer: a) Odd
Explanation: The rightmost column sums to \(1+1+1=3_{10}\). In binary, \(3_{10}\) is \(11_{2}\).
87. The input hexadecimal representation of 1110 is ___.
a) 0111
b) E
c) 15
d) 14
Answer: b) E
Explanation: The binary number 1110 is equivalent to the decimal number 14.
In hexadecimal notation, the decimal value 14 is represented by the letter E
88. The octal equivalent of the binary number (010010100)2 is ____
a) 422
b) 242
c) 224
d) 226
Answer: c) 224
Explanation: The octal equivalent of the binary number \((010010100)_{2}\) is a) 224
89. 1-byte ASCII character = ? bits
a) 6
b) 7
c) 8
d) 16
Answer: c) 8
Explanation: Extended ASCII uses 8 bits for 256 characters.
90. *@Ac# is a type of ____ data.
a) Symbolic
b) Alphanumeric
c) Alphabetic
d) Numeric
Answer: b) Alphanumeric
Explanation: Alphanumeric data refers to data that contains a combination of alphabetic characters (A-Z), numeric digits (0-9), and usually includes special characters or symbols (like *, @, and #).
91. Which of the following is not a type of computer code?
a) EBCDIC
b) BCD
c) ASCII
d) EDIC
Answer: d) EDIC
Explanation: EDIC is not a standard type of computer code used for character encoding.
EBCDIC, BCD, and ASCII are all valid and widely used types of computer codes.
92. The BCD representation of (94)10 is ____
a) 10010100
b) 11000111
c) 1100001
d) None of these
Answer: a) 10010100
Explanation: The BCD (Binary Coded Decimal) representation of \((94)_{10}\) is a) 10010100.
93. BCD addition: 9 + 7 = ?
a) 10000
b) 0001 0110
c) 0010 0000
d) 1001 0111
Answer: b) 0001 0110
Explanation: 9+7=16 → BCD adjust → 0001 0110.
Answer: b) 0001 0110
Explanation: 9+7=16 → BCD adjust → 0001 0110.
94. What does ASCII stand for?
a) American Standard Code for Information Interchange
b) American Scientific Code for Information Interchange
c) American Scientific Code for Interchanging Information
d) American Standard Code for Interchanging Information
Answer: a) American Standard Code for Information Interchange
Explanation: ASCII is the standard acronym in computing and telecommunications for the character encoding scheme that underpins much of the modern digital world. It was developed to provide a consistent way for computers to represent text data.
95. Which of the following is not a binary number?
a) 001
b) 101
c) 202
d) 110
Answer: c) 202
Explanation: The binary number system is a base-2 system that uses only two digits: 0 and 1.
The number 202 contains the digit 2, which is not a valid digit in the binary system.
96. ASCII code for capital letter ‘A’ = ?
a) 65
b) 66
c) 67
d) 68
Answer: a) 65
Explanation: The ASCII (American Standard Code for Information Interchange) standard assigns a unique decimal number to each character. Uppercase letters ‘A’ through ‘Z’ have sequential ASCII values starting from 65 up to 90.
97. Decimal equivalent of (1111)2 is
a) 11
b) 10
c) 1
d) 15
Answer: d) 15
Explanation: “Decimal Value”=(1×2^3)+(1×2^2)+(1×2^1)+(1×2^0)
“Decimal Value”=(1×8)+(1×4)+(1×2)+(1×1)
Decimal Value=(1×8)+(1×4)+(1×2)+(1×1)
“Decimal Value”=8+4+2+1
Decimal Value=8+4+2+1
98. LSD stands as
a) Long Significant Digit
b) Least Significant Digit
c) Large Significant Digit
d) Longer Significant Decimal
Answer: b) Least Significant Digit
Explanation: LSD stands for Least Significant Digit. It is the rightmost digit in a number and has the lowest positional value or weight.
99. Gate is also known as inverter.
a) OR
b) NOT
c) XOR
d) NAND
Answer: b) NOT
Explanation: A NOT gate is the fundamental logic gate that performs logical negation or inversion.
100. Extended ASCII supports:
a) 128 characters
b) 256 characters
c) 512 characters
d) 65,536 characters
Answer: b) 256
Explanation: 8-bit ASCII allows 256 characters.