Q#1: Which logic gate is used for addition in digital circuits?
(A) AND
(B) OR
(C) XOR
(D) NOT
Answer: (C) XOR
Q#2: What is the basic building block of digital circuits?
(A) Transistor
(B) Capacitor
(C) Inductor
(D) Diode
Answer: (A) Transistor
Q#3: Which gate has an output that is the complement of its input?
(A) OR
(B) NOT
(C) XOR
(D) NAND
Answer: (B) NOT
Q#4: How many input combinations are possible for a 3-input logic gate?
(A) 4
(B) 8
(C) 16
(D) 32
Answer: (B) 8
Q#5: Which logic gate is also known as the Universal Gate?
(A) OR
(B) NAND
(C) XOR
(D) NOR
Answer: (B) NAND
Q#6: In Boolean algebra, what is the complement of AND operation?
(A) OR
(B) NAND
(C) XOR
(D) NOT
Answer: (B) NAND
Q#7: What is the output of an XOR gate if both inputs are HIGH (1)?
(A) 0
(B) 1
(C) Depends on the circuit
(D) Undefined
Answer: (A) 0
Q#8: Which logic gate is used for arithmetic operations in computers?
(A) AND
(B) OR
(C) XOR
(D) ALU
Answer: (D) ALU
Q#9: What is the Boolean expression for the OR operation?
(A) A’B’
(B) AB
(C) A + B
(D) A ⊕ B
Answer: (C) A + B
Q#10: What is the truth table for a NOT gate?
| A | Q |
|---|---|
| 0 | 1 |
| 1 | 0 |
Answer: (A)
Q#11: What is the Boolean equation for a NAND gate?
(A) A’B’
(B) AB
(C) A + B
(D) A ⊕ B
Answer: (A) A’B’
Q#12: Which gate has an output of 1 only if all inputs are 0?
(A) AND
(B) OR
(C) XOR
(D) NOR
Answer: (D) NOR
Q#13: In a 4-bit binary adder, what is the maximum decimal sum possible?
(A) 7
(B) 8
(C) 15
(D) 16
Answer: (C) 15
Q#14: Which logic gate is equivalent to the Boolean expression (A + B)’?
(A) NOT
(B) NAND
(C) XOR
(D) NOR
Answer: (B) NAND
Q#15: What is the output of an OR gate if both inputs are LOW (0)?
(A) 0
(B) 1
(C) Depends on the circuit
(D) Undefined
Answer: (A) 0