Number Systems & Logic MCQs 2026

45 questions with detailed answers · 18 from past papers · 5 quiz batches available

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Page 1 of 1Questions 1–10 of 45

Q1Past Paper · PPSC/FPSC/NTSmedium
Standard ASCII uses how many bits to represent a character
1. A8
2. B7
3. C16
4. D4
💡 Explanation:
Standard ASCII uses 7 bits per character.
Q2Past Paper · PPSC/FPSC/NTSmedium
Boolean algebra was developed by
1. ACharles Babbage
2. BAlan Turing
3. CGeorge Boole
4. DJohn Napier
💡 Explanation:
George Boole developed Boolean algebra, the basis of digital logic.
Q3medium
A logic gate that outputs 1 only when its inputs are different is the
1. AAND gate
2. BOR gate
3. CNOT gate
4. DXOR gate
💡 Explanation:
An XOR gate outputs 1 only when its inputs differ.
Q4medium
The NOT gate is also called a/an
1. AInverter
2. BBuffer
3. CAdder
4. DComparator
💡 Explanation:
A NOT gate is also known as an inverter.
Q5Past Paper · PPSC/FPSC/NTSmedium
Which of the following is called a universal gate
1. AAND
2. BOR
3. CNAND
4. DXOR
💡 Explanation:
NAND (and NOR) are universal gates that can build any other gate.
Q6easy
How many inputs does a basic NOT gate have
1. A2
2. B1
3. C3
4. D4
💡 Explanation:
A basic NOT gate has a single input.
Q7medium
The AND gate output is 0 when
1. ABoth inputs are 1
2. BBoth inputs are high
3. COne input is 1
4. DAt least one input is 0
💡 Explanation:
An AND gate outputs 0 whenever at least one input is 0.
Q8medium
The OR gate output is 0 only when
1. AAll inputs are 0
2. BAll inputs are 1
3. COne input is 1
4. DInputs are different
💡 Explanation:
An OR gate outputs 0 only when all inputs are 0.
Q9Past Paper · PPSC/FPSC/NTSmedium
ASCII stands for
1. AAmerican Standard Communication Interface
2. BAdvanced Standard Code
3. CAmerican Standard Code for Information Interchange
4. DAutomatic Standard Code Interface
💡 Explanation:
ASCII stands for American Standard Code for Information Interchange.
Q10Past Paper · PPSC/FPSC/NTSeasy
A binary digit is also called a
1. ABit
2. BByte
3. CNibble
4. DWord
💡 Explanation:
A binary digit (0 or 1) is called a bit.
Q11Past Paper · PPSC/FPSC/NTSeasy
The binary number system has a base of
1. A8
2. B2
3. C10
4. D16
💡 Explanation:
The binary number system uses base 2 (digits 0 and 1).
Q12Past Paper · PPSC/FPSC/NTSeasy
The hexadecimal number system has a base of
1. A2
2. B8
3. C10
4. D16
💡 Explanation:
The hexadecimal number system uses base 16.
Q13Past Paper · PPSC/FPSC/NTSeasy
The octal number system has a base of
1. A8
2. B2
3. C10
4. D16
💡 Explanation:
The octal number system uses base 8 (digits 0 to 7).
Q14Past Paper · PPSC/FPSC/NTSeasy
The decimal number system has a base of
1. A2
2. B8
3. C10
4. D16
💡 Explanation:
The decimal number system uses base 10.
Q15easy
How many digits are used in the binary system
1. A1
2. B2
3. C8
4. D10
💡 Explanation:
Binary uses only two digits: 0 and 1.
Q16medium
Which digits are used in the octal number system
1. A0-9
2. B0 and 1
3. C0-F
4. D0-7
💡 Explanation:
Octal uses the digits 0 through 7.
Q17Past Paper · PPSC/FPSC/NTSmedium
In hexadecimal, the letter A represents the decimal value
1. A10
2. B11
3. C12
4. D15
💡 Explanation:
In hexadecimal, A equals decimal 10.
Q18Past Paper · PPSC/FPSC/NTSmedium
In hexadecimal, the letter F represents the decimal value
1. A10
2. B13
3. C15
4. D16
💡 Explanation:
In hexadecimal, F equals decimal 15.
Q19easy
The decimal number 2 in binary is
1. A01
2. B10
3. C11
4. D00
💡 Explanation:
Decimal 2 is written as 10 in binary.
Q20medium
The decimal number 5 in binary is
1. A100
2. B110
3. C111
4. D101
💡 Explanation:
Decimal 5 equals 101 in binary (4+1).
Q21medium
The decimal number 8 in binary is
1. A1000
2. B1010
3. C1100
4. D0100
💡 Explanation:
Decimal 8 equals 1000 in binary.
Q22Past Paper · PPSC/FPSC/NTSmedium
The binary number 1010 equals which decimal number
1. A8
2. B12
3. C10
4. D6
💡 Explanation:
Binary 1010 equals 8+0+2+0 = 10 in decimal.
Q23medium
The binary number 111 equals which decimal number
1. A5
2. B7
3. C6
4. D8
💡 Explanation:
Binary 111 equals 4+2+1 = 7 in decimal.
Q24Past Paper · PPSC/FPSC/NTShard
The decimal number 255 in binary is
1. A11110000
2. B10000000
3. C11111110
4. D11111111
💡 Explanation:
Decimal 255 equals 11111111 in binary (eight 1s).
Q25medium
BCD stands for
1. ABinary Coded Decimal
2. BBasic Coded Digit
3. CBinary Computer Data
4. DByte Coded Decimal
💡 Explanation:
BCD stands for Binary Coded Decimal.
Q26Past Paper · PPSC/FPSC/NTSmedium
How many characters can standard 7-bit ASCII represent
1. A64
2. B256
3. C512
4. D128
💡 Explanation:
7-bit ASCII can represent 2^7 = 128 characters.
Q27medium
The rightmost bit in a binary number is called the
1. AMSB
2. BParity bit
3. CLSB
4. DSign bit
💡 Explanation:
The rightmost bit is the Least Significant Bit (LSB).
Q28medium
The leftmost bit in a binary number is called the
1. ALSB
2. BMSB
3. CCarry bit
4. DStop bit
💡 Explanation:
The leftmost bit is the Most Significant Bit (MSB).
Q29Past Paper · PPSC/FPSC/NTSmedium
In binary addition, 1 + 1 equals
1. A1
2. B11
3. C100
4. D10
💡 Explanation:
In binary, 1 + 1 equals 10 (0 with a carry of 1).
Q30Past Paper · PPSC/FPSC/NTSmedium
A logic gate that outputs 1 only when all inputs are 1 is the
1. AAND gate
2. BOR gate
3. CNOT gate
4. DXOR gate
💡 Explanation:
An AND gate outputs 1 only when all of its inputs are 1.
Q31Past Paper · PPSC/FPSC/NTSmedium
A logic gate that outputs 1 when at least one input is 1 is the
1. AAND gate
2. BNOT gate
3. COR gate
4. DNAND gate
💡 Explanation:
An OR gate outputs 1 when at least one input is 1.
Q32Past Paper · PPSC/FPSC/NTSmedium
A logic gate that reverses or inverts its input is the
1. AAND gate
2. BNOT gate
3. COR gate
4. DXOR gate
💡 Explanation:
A NOT gate inverts its single input.
Q33medium
The binary number 1111 equals which decimal number
1. A7
2. B8
3. C14
4. D15
💡 Explanation:
Binary 1111 equals 8+4+2+1 = 15 in decimal.
Q34medium
The hexadecimal number system is often used because it is
1. ASlower
2. BA shorthand for binary
3. CBase 10
4. DOnly for text
💡 Explanation:
Hexadecimal is a compact shorthand for representing binary values.
Q35medium
The decimal number 10 in hexadecimal is
1. AA
2. B10
3. CF
4. DB
💡 Explanation:
Decimal 10 equals A in hexadecimal.
Q36medium
The octal number 10 equals which decimal number
1. A2
2. B10
3. C8
4. D16
💡 Explanation:
Octal 10 equals decimal 8.
Q37medium
The base of a number system is also called its
1. ADigit
2. BRadix
3. CBit
4. DNibble
💡 Explanation:
The base of a number system is also known as its radix.
Q38easy
The decimal number 4 in binary is
1. A100
2. B010
3. C110
4. D011
💡 Explanation:
Decimal 4 equals 100 in binary.
Q39medium
A NAND gate is an AND gate followed by a
1. AOR gate
2. BXOR gate
3. CBuffer
4. DNOT gate
💡 Explanation:
A NAND gate is an AND gate whose output is inverted by a NOT gate.
Q40medium
The hexadecimal digit C represents which decimal value
1. A10
2. B11
3. C12
4. D13
💡 Explanation:
In hexadecimal, C equals decimal 12.
Q41easy
Which number system is most convenient for humans in daily life
1. ABinary
2. BDecimal
3. COctal
4. DHexadecimal
💡 Explanation:
The decimal system is the most convenient for everyday human use.
Q42medium
The output of an XOR gate when both inputs are 1 is
1. A0
2. B1
3. CUndefined
4. DHigh
💡 Explanation:
An XOR gate outputs 0 when both inputs are equal (1 and 1).
Q43easy
Which of the following is NOT a valid binary digit
1. A0
2. B1
3. CBoth 0 and 1 are valid
4. D2
💡 Explanation:
2 is not a valid binary digit; binary uses only 0 and 1.
Q44easy
The number of bits in a nibble is
1. A2
2. B8
3. C4
4. D16
💡 Explanation:
A nibble consists of 4 bits.
Q45medium
Which gate is known as the inverted OR gate
1. AAND
2. BXOR
3. CNAND
4. DNOR
💡 Explanation:
A NOR gate is an OR gate with an inverted output.

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