Objective Questions on Logic Gate

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Objective Questions on Logic Gate

Objective Questions on Logic Gate, digital logic gate questions, MCQ on logic gate, digital logic design multiple-choice questions, Engineering MCQ, Multiple Choice Question based on Engineering, Digital Electronics MCQ, AND Gate MCQ, OR Gate MCQ, NAND Gate MCQ

MULTIPLE CHOICE QUESTIONS

  1. If A, B and C are the inputs of AND gate, then the output Y is HIGH for
  • A = 1, B = 1, C = 0
  • A = 0, B = 0, C = 0
  • A = 1, B = 1, C = 1
  • A = 1, B = 0, C = 1

Answer: A = 1, B = 1, C = 1

2. NAND gate is

  • AND followed by NOT
  • NOT followed by AND
  • Two AND gates interconnected
  • OR followed by AND

Answer: AND followed by NOT

3. If one of the inputs of the 2-input logic gate is LOW, then which of the following gate still has a HIGH output is HIGH?

  • AND
  • NAND
  • NOR
  • OR

Answer: NAND

4. The Boolean expression for a 3-input AND gate is

  • Y = AB + BC + CA
  • Y = ABC
  • Y = A + B + C
  • Y = AB + C

Answer: Y = ABC

5. Which of the following logical operations has ‘+’ as its symbol?

  • AND
  • NAND
  • OR
  • NOT

Answer: OR

6. The logic expression for a NOR gate is given as

  • X=\bar{A}+B
  • X=A+\bar{B}
  • X=A+B
  • X=\bar{A+B}

Answer: X=\bar{A+B}

7. The Boolean expression for the output of a NOR gate is similar to a

  • NAND gate followed by an inverter
  • OR gate followed by an inverter
  • AND gate followed by an inverter
  • NOR gate followed by an inverter

Answer: OR gate followed by an inverter

8. A NOT gate has a HIGH output when

  • The input is LOW
  • The input is HIGH
  • Power supply is ON
  • Power supply is OFF

Answer: The input is LOW

9. An exclusive-OR gate has a HIGH output when

  • All inputs are LOW
  • All inputs are HIGH
  • The inputs have opposite logic
  • None of the above

Answer: The inputs have opposite logic

10. Which of the following gates are interchangeable?

  • NAND and NOR
  • NOR and OR
  • AND and OR
  • NOR and bubbled OR

Answer: NAND and NOR

11. A 2-input NOR gate is equivalent to a

  • Negative-OR gate
  • Negative-AND gate
  • Negative-NAND gate
  • None of the above

Answer: Negative-AND gate

12. The output ‘Y’ of the given logic diagram is

Objective Questions on Logic Gate
  • Y = (A + B) C
  • Y = AB + C
  • Y = A + B + C
  • Y = A + BC

Answer: Y = (A + B) C

13. The Boolean expression for XNOR is given as

  • A+B
  • A.B
  • A \oplus B
  • \bar{A \oplus B}

Answer: A \oplus B

14. A Combinational circuit can be designed using only

  • AND gates
  • OR gates
  • OR and X-NOR gates
  • NOR gates

Answer: NOR gates

15. How many NOR gates are required to obtain AND operations?

  • 2
  • 3
  • 4
  • 5

Answer: 3

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