1. What is the number of outputs of a full adder circuit?
1) Two
2) Three
3) Four
4) One
Solution: 2) Three
How a full adder works? Check Here!
2. What is the expression for the sum(s) of a half adder if the inputs are A & B?
1) S = A OR B
2) S = A AND B
3) S = A XNOR B
4) S = A XOR B
Solution: 4) A XOR B
3. What is the sum(S) expression of a full adder if the inputs are A, B & C?
1) S = A OR B AND C
2) S = A AND B OR C
3) S = A XNOR B XOR C
4) S = A XOR B XOR C
Solution: 4) A XOR B XOR C
4. What is the result of the binary sum?
10101 + 1011
Do you know how to perform binary addition in digital electronics? Click to know!
1) 1 0 0 0 0
2) 1 0 1 0 1 0
3) 1 0 0 0 0 0
4) 1 1 1 1 0 0
Solution: 3) 1 0 0 0 0 0
5. Which of these following logic gates gives a high output when both the inputs are low?
1) NOR gate
2) NOT gate
3) NAND gate
4) ALL OF THE ABOVE
Solution: 4) ALL OF THE ABOVE
6. Which of these following does not include in an ALU (Arithmetic Logic Unit)?
1) Adder
2) Subtractor
3) Multiplexer
4) None of the above
Solution: 3) Multiplexer
How a multiplexer works? Find out in detail!
7. which logic gate itself is a combinational circuit?
1) XOR
2) NAND
3) NOR
4) NOT
Solution: 1) XOR
8. How many bits does the sum of the full adder consists of?
1) Four bits
2) Three bits
3) Two bits
4) Five bits
Solution: 3) Two bits
9. A combinational circuit calculates the arithmetic sum in a parallel way. What is the name of the adder?
1) Sequential Adder
3) Serial Adder
4) Both 1) & 2)
Solution: 2) Parallel Adder
10. What is the primary object that is needed for VLSI technology?
1) NOR gate
2) NAND gate
3) Both 1) and 2)
4) Gate array
Solution: 4) Gate array.
11. Choose whether the below-given statement is true or false.
Statement: A binary subtractor can be made using a binary adder.
- True
- False
Solution: (1). True
How binary adders can make binary subtractors! Click to know!
12. A circuit takes single input but provides multiple outputs. Identify which circuit it could be.
1) Multiplexer
2) Demultiplexer
4) All of them
Solution: 2) Demultiplexer
13. What does a multiplexer do?
1) It takes multiple inputs and provides a single output.
2) It takes a single output and offers multiple outputs.
3) It inverts the input.
4) None of the above.
Solution: 1) It takes multiple inputs and provides a single output.
14. A half subtractor provides how many outputs?
1) One
2) Four
3) Three
4) Two
Solution: 4) Two
15. Mark the given statement as True or false.
Statement: An Encoder can be used as a transducer.
- True
- False
Solution: (1). True
16. How does a priority set?
1) The lower the subscript number, the higher the priority.
2) The higher the subscript number, the lower the priority.
3) The higher the subscript number, the higher the priority.
4) None of the above.
Solution: 3) The higher the subscript number, the higher the priority.
17. Find out the result of the BCD addition.
0110 + 0101
1) 10001
2) 11001
3) 1011
4) 1111
Solution: 1) 10001
18. Find out the result of the binary subtraction?
1101 – 1011
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1) 10001
2) 0010
3) 1011
4) 0001
Solution: 2) 0010
19. Mark the given statement as True or false.
Statement: The logical expression for both the full adders and full subtractors are the same.
- True
- False
Solution: (1). True
20. Which type of complement method is used for the decimal number system?
1) 10’s compliment
2) 8’s compliment
3) 9’s compliment
4) Both 1) and 3)
Solution: 4) Both 1) and 3)
21. How many select lines will be there if the inputs of a MUX are 8?
1) One
2) Four
3) Three
4) Five
Solution: 3) Three
22. How many select lines will be there if the inputs of a DEMUX are 4?
1) One
2) Five
3) Three
4) Two
Solution: 1) Two
23. Recording a video clip is which type of operation?
1) Multiplexing
2) De Multiplexing
3) Encoding
4) Decoding
Solution: 3) Encoding
24. A half binary adder is implemented using basic gates. How many and gates will be required?
1) One
2) Two
3) Three
4) Four
Solution: 1) One
25. Mark the given statement as True or false.
Statement: Multiplexers cannot implement Boolean functions.
- True
- False
Solution: (2). False
26. Which circuit can perform the increment operation of an ALU?
1) Adder
2) Subtractor
3) Both 1) and 2)
4) None of them
Solution: 3) Both 1) and 2)
27. Mark the given statement as True or false.
Statement: Technologies like TDM, FDM, CDMA, etc., uses multiplexers and demultiplexers.
- True
- False
Solution: (1). True
28. A decoder has an output of 2n. How many inputs does it consume?
1) n
2) 2n
3) 2n – 1
4) n-1
Solution: 1) n
29. Which type of basic gates is most necessary for Encoders?
1) OR gates
2) AND gates
3) NOT gates
4) All of the above
Solution: 1) OR gates
30. Mark the given statement as True or false.
Statement: DTMF is Diode Time Multiplexer Frequency.
- True
- False
Solution: (2). False. DTMF – DUAL TONE MULTIPLE FREQUENCY.
31. What is the lowest number of NAND gates required for a half subtractors?
1) Four
2) Five
3) Six
4) Seven
Solution: 2) Five
32. A decoder has four input lines. How many output lines will be there?
1) Eight
2) One
3) Four
4) Sixteen
Solution: 4) Sixteen
33. Mark the given statement as True or false.
Statement: An encoder takes multiple data inputs and converts them into a single output with select lines.
- True
- False
Solution: (2). False
34. What is min-term?
1) Product of sum
2) Sum of product
3) Product of product
4) Sum of the sum
Solution: 1) Product of sum
35. Find the application of a MUX.
1) It is used in Analog to Digital converters and Digital to analog converters in digital electronics.
2) It is used in rectifiers.
3) It is used in filters.
4) None of the above is correct.
Solution: 1) It is used in Analog to Digital converters and Digital to analog converters in digital electronics.
36. Mark the given statement as True or false.
Statement: An operation in Flip Flop is faster than an operation in the multiplexer.
- True
- False
Solution: (2). False
37. Which IC works as a multiplexer?
1) 74HA198
2) 74HC150
3) 74CH199
4) 74HC157
Solution: 4) 74HC157
38. Which IC works as a demultiplexer?
1) 74HC83
2) 74HC38
3) 74CH19
4) 74HC15
Solution: 1) 74HC83
39. Which IC works as Encoder?
1) HT85A
2) HT87B
3) HT12E
4) HT74F
Solution: 3) HT12E
40. What is the lowest no. of OR gate required for the given expression?
Y = A’B + B’A
1) 1
2) 2
3) 4
4) 5
Solution: 1) 1
41. What is the lowest no. of AND gate required for the given expression?
Y = A’B + B’A
1) 1
2) 2
3) 4
4) 5
Solution: 2) 2
42. What is the lowest no. of NAND gates required to make an inverter?
1) 1
2) 2
3) 3
4) 4
Solution: 1) 1
43. What is the lowest no. of NOR gates required to make an OR gate?
1) 1
2) 2
3) 3
4) 4
Solution: 2) 2
44. Which gates are known as universal gates in digital electronics ?
1) OR and AND
2) NOT and XOR
3) NOR and NAND
4) All of them
Solution: 3) NOR and NAND
45. A truth table is given below where A and B are the provided inputs, and from Y the output is taken. Identify the Logic gate.
1) XOR
2) NAND
3) XNOR
4) NOR
Solution: 3) XNOR
46. A truth table is given below where A and B are the provided inputs, and from Y the output is taken, for a digital electronics circuitry. Identify the Logic gate.
1) XOR
2) NAND
3) XNOR
4) NOR
Solution: 4) NOR
47. Find the odd one out from the digital electronics circuitry.
1) MULTIPLEXER
2) FLIP/FLOPS
3) REGISTERS
4) COUNTERS
Solution: 1) MULTIPLEXER
48. What is the lowest no. of NOT gate required for the given expression?
Y = A’B + B’C + AC
1) 1
2) 2
3) 3
4) 4
Solution: 1) 1
49. Find the odd one out.
1) DEMULTIPLEXERS
2) ENCODERS
3) HALF ADDERS
4) FULL SUBTRACTORS
Solution: 1) DEMULTIPLEXERS
50. A truth table is given below where A and B are the provided inputs, and from Y the output is taken, for a digital electronics circuitry. Identify the combinational circuit.
| A | B | Y |
| LOW | LOW | LOW |
| LOW | HIGH | HIGH |
| HIGH | LOW | HIGH |
| LOW | LOW | LOW |
1) SUBTRACTOR
2) MULTIPLEXER
3) ADDER
4) Both 1) and 3)
Solution: 4) Both 1) and 3)
Conclusion : With these we are done with the critical Digital Electronics MCQs and To learn more on Digital Electronics Article and Question Answers click here
Hi, I am Sudipta Roy. I have done B. Tech in Electronics. I am an electronics enthusiast and am currently devoted to the field of Electronics and Communications. I have a keen interest in exploring modern technologies such as AI & Machine Learning. My writings are devoted to providing accurate and updated data to all learners. Helping someone in gaining knowledge gives me immense pleasure.
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