1. The output of an AND gate is high (1) when:
A. All inputs are high (1)
B. At least one input is high (1)
C. All inputs are low (0)
D. At least one input is low (0)
Answer: A. All inputs are high (1)
2. The output of an OR gate is high (1) when:
A. All inputs are low (0)
B. At least one input is high (1)
C. All inputs are high (1)
D. At least one input is low (0)
Answer: B. At least one input is high (1)
3. The output of a NOT gate is:
A. The same as the input
B. The complement of the input
C. Always high (1)
D. Always low (0)
Answer: B. The complement of the input
4. The output of a NAND gate is high (1) when:
A. All inputs are low (0)
B. At least one input is low (0)
C. All inputs are high (1)
D. None of the above
Answer: B. At least one input is low (0)
5. The output of a NOR gate is high (1) when:
A. All inputs are low (0)
B. At least one input is high (1)
C. All inputs are high (1)
D. None of the above
Answer: A. All inputs are low (0)
6. The output of an XOR (exclusive OR) gate is high (1) when:
A. The inputs are the same
B. The inputs are different
C. Both inputs are high (1)
D. Both inputs are low (0)
Answer: B. The inputs are different
7. The output of an XNOR gate is high (1) when:
A. The inputs are different
B. Both inputs are low (0)
C. Both inputs are high (1)
D. The inputs are the same
Answer: D. The inputs are the same
Truth Tables
8. The truth table for a 2-input AND gate is:
| A | B | Output |
|---|---|---|
| 0 | 0 | 0 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 1 |
Which statement is true?
A. The output is 1 only when both inputs are 0
B. The output is 1 only when both inputs are 1
C. The output is 0 when at least one input is 1
D. The output is 0 only when both inputs are 0
Answer: B. The output is 1 only when both inputs are 1
9. The truth table for a 2-input OR gate is:
| A | B | Output |
|---|---|---|
| 0 | 0 | 0 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 1 |
Which statement is true?
A. The output is 1 when at least one input is 1
B. The output is 0 when both inputs are 1
C. The output is 1 only when both inputs are 0
D. The output is 0 when at least one input is 1
Answer: A. The output is 1 when at least one input is 1
10. The truth table for a 2-input NOT gate is:
| A | Output |
|---|---|
| 0 | 1 |
| 1 | 0 |
Which statement is true?
A. The output is the same as the input
B. The output is the complement of the input
C. The output is always high (1)
D. The output is always low (0)
Answer: B. The output is the complement of the input
11. A NAND gate is a combination of which two gates?
A. OR and NOT
B. AND and NOT
C. NOR and OR
D. XOR and XNOR
Answer: B. AND and NOT
12. A NOR gate is a combination of which two gates?
A. OR and NOT
B. AND and NOT
C. XOR and NOT
D. NOT and XNOR
Answer: A. OR and NOT
13. An XOR gate is often used in circuits that perform:
A. Addition
B. Subtraction
C. Multiplication
D. Division
Answer: A. Addition
14. Which of the following gates is known as a universal gate?
A. AND
B. OR
C. NOT
D. NAND
Answer: D. NAND
15. Which gate is commonly used for digital subtraction?
A. AND
B. OR
C. XOR
D. XNOR
Answer: C. XOR
16. An XNOR gate is often used to check if two values are:
A. Equal
B. Greater
C. Less
D. Different
Answer: A. Equal
17. What is the output of an XOR gate when both inputs are 0?
A. 0
B. 1
C. Undefined
D. 10
Answer: A. 0
18. In a 3-input AND gate, the output will be 1 only if:
A. All three inputs are 0
B. At least two inputs are 1
C. All three inputs are 1
D. At least one input is 1
Answer: C. All three inputs are 1
19. Which of the following is the correct Boolean expression for the AND gate?
A. A + B
B. A • B
C. A’ + B
D. A’ • B
Answer: B. A • B
20. Which of the following is the correct Boolean expression for the OR gate?
A. A + B
B. A • B
C. A’ + B
D. A’ • B
Answer: A. A + B
21. The De Morgan’s law states that:
A. (A + B)’ = A’ • B’
B. (A • B)’ = A’ + B’
C. Both A and B are correct
D. None of the above
Answer: C. Both A and B are correct
22. In a circuit with a NAND gate, what would be the output if both inputs are 1?
A. 1
B. 0
C. Undefined
D. Both 0 and 1
Answer: B. 0