**Digital Electronics MCQ with Answer**

**Q1. Using the laws of Boolean algebra, the Boolean expression AB + (A+B)(B+C) can be simplified to**

(a) *A â€“ BC*

(b) *B + AC*

(c) *C + AB*

(d) *AB + AC*

**Q2. Which of the following gates is known as equality comparator?**

(a) AND gate

(b) OR gate

(c) XNOR gate

(d) XOR gate

**Q3. 10101 binary number corresponds to decimal number**

(a) 31

(b) 21

(c) 11

(d) 3

**Q4. The unique output for a NAND logic gate is a 0 :**

(a) when all inputs are 0

(b) when all inputs are 1

(c) when any one input is 0

(d) when any one input is 1

**Q5. Bubbled (inputs inverted) OR gate is equivalent to**

(a) NOR gate

(b) NAND gate

(C) NOT gate

(d) XNOR gate

**Q6. The minimum number of two input NAND gates required to realize the function of 3 input OR gate is**

(a) 4

(b) 5

(C) 6

(d) 3

**Q7. A bubbled (input inverted) OR gate is equivalent to**

(a) NOR gate

(b) NAND gate

(c) NOT gate

(d) XNOR gate

**Q8. The most suitable gate for comparing two bits is**

(a) AND

(b) OR

(C) NAND

(d) X-OR

**Q9. Which of the following gates cannot be used as an inverter ?**

(a) NAND

(b) AND

(C) NOR

(d) X-NOR

**Q10. How many NOR gates are required to obtain AND operation ?**

(a) 2

(b) 3

(c) 4

(d) 1

**Q11. Which of the following is a universal gate ?**

(a) OR gate

(b) NOR gate

(c) AND gate

(d) NOT gate

**Q12. Consider a Boolean Expression F = (B + BC)(B + Bâ€™C)(B + D) The minimum number of NAND gates required to implement this â€˜Fâ€™ will be**

(a) 0

(b) 2

(c) 3

(d) 4

**Q13. The number of comparators in a 4-bit flash A to D converter is**

(a) 4

(b) 5

(c) 15

(d) 16

**Q14. The minimum number of storage elements needed for the designing of a bi-stable multivibrator is:**

(a) 0

(b) 1

(c) 2

(d) 3

**Q15. The functional difference between SR flip-flop and JK flip-flop is that**

(a) JK flip-flop has a feedback path

(b) JK flip-flop can accept both inputs as 1

(c) JK flip-flop does not require an external clock pulse

(d) JK flip-flop is faster than SR flip-flop

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*Answer Key* (if you find any answer wrong, feel free to Correct us)

*Answer Key*

01. | (b) | 06. | (d) | 11. | (b) |

02. | (c) | 07. | (d) | 12. | (a) |

03. | (b) | 08. | (c) | 13. | (c) |

04. | (b) | 09. | (b) | 14. | (b) |

05. | (b) | 10. | (a) | 15. | (b) |