Digital Electronics Quiz Answers and Explanations

What is the basic unit of digital information?

  • a) Byte
  • b) Bit
  • c) Nibble
  • d) Word

Answer: b) Bit

Explanation: A bit (binary digit) is the most fundamental unit of digital information, representing either a 0 or 1.


Which logic gate performs the operation where the output is true only if all inputs are true?

  • a) OR gate
  • b) NOR gate
  • c) AND gate
  • d) XOR gate

Answer: c) AND gate

Explanation: The AND gate outputs true (1) only when all of its inputs are true (1).


What is the decimal equivalent of the binary number 1010?

  • a) 8
  • b) 10
  • c) 12
  • d) 14

Answer: b) 10

Explanation: In binary, 1010 represents (1×8) + (0×4) + (1×2) + (0×1) = 8 + 0 + 2 + 0 = 10 in decimal.


Which of the following is NOT a type of flip-flop?

  • a) D flip-flop
  • b) T flip-flop
  • c) K flip-flop
  • d) JK flip-flop

Answer: c) K flip-flop

Explanation: Common types of flip-flops include D, T, SR, and JK. There is no standard “K flip-flop.”


What does ROM stand for in digital electronics?

  • a) Random Operating Memory
  • b) Read-Only Memory
  • c) Rapid Output Module
  • d) Reliable Oscillator Mechanism

Answer: b) Read-Only Memory

Explanation: ROM stands for Read-Only Memory, which is a type of non-volatile memory that stores data permanently.


Which of the following is a universal gate?

  • a) OR gate
  • b) AND gate
  • c) NOT gate
  • d) NAND gate

Answer: d) NAND gate

Explanation: A NAND gate is considered universal because any other logic gate can be constructed using only NAND gates.


In Boolean algebra, what does the symbol “+” represent?

  • a) Addition
  • b) Multiplication
  • c) OR operation
  • d) XOR operation

Answer: c) OR operation

Explanation: In Boolean algebra, the “+” symbol represents the logical OR operation, not arithmetic addition.


What is the purpose of a multiplexer (MUX) in digital circuits?

  • a) To combine multiple digital signals into one
  • b) To split one digital signal into multiple signals
  • c) To amplify digital signals
  • d) To convert analog signals to digital

Answer: a) To combine multiple digital signals into one

Explanation: A multiplexer selects one of several input signals and forwards it to a single output line.


Which of the following represents the hexadecimal equivalent of decimal 255?

  • a) FF
  • b) EE
  • c) 11111111
  • d) 1111

Answer: a) FF

Explanation: Decimal 255 is equivalent to binary 11111111, which in hexadecimal is represented as FF.


What is the function of a full adder in digital circuits?

  • a) To subtract two binary numbers
  • b) To add two single bits
  • c) To add three single bits
  • d) To multiply two binary numbers

Answer: c) To add three single bits

Explanation: A full adder adds three single bits: two input bits and one carry bit from a previous addition.


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