**Digital Electronics MCQ**

**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!*

*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**

**Critical Electronics MCQ Series**

**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!*

*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.*

*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.*

*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*

*0110 + 0101*

1) 10001

2) 11001

3) 1011

4) 1111

**Solution: 1) 10001**

**18. Find out the result of**** the binary subtraction?**

*1101 – 1011*

*1101 – 1011*

*Do you know how to perform binary subtraction in digital electronics? Click to know!*

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.*

*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.*

*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. *

*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.*

*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. *

*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.*

*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.**

**A truth table is given below where A and B are the provided inputs, and from Y the output is taken**

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 truth table is given below where A and B are the provided inputs, and from Y the output is taken**

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*

*To learn more on Digital Electronics Article and Question Answers click here*

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