Combinational Logic Circuits MCQs

Digital Electronics MCQs

1. Consider the following statements: 

1. When a MUX is used to implement a logic function, the logic variables are applied to the MUX's data inputs.
2. The circuit for a DEMUX is basically the same as that for a decoder.

Of these:

a. Both statements are false

b. Statement-1 is false while statement-2 is correct

c. Both the statements are correct

d. Statement-1 is correct while 2 is false

2. The logic function F(A, B, C) = Σ (1, 3, 5, 6) can be implemented using:

a. One 4x1 MUX

b. One 4x1 MUX and an OR gate

c. One 4x1 MUX and a AND gate

d. One 4x1 MUX and a NOT gate

3. A certain multiplexer can switch one of 32 data inputs to its output. The number of control inputs in this multiplexer is_____.

a. 8 

b. 5

c. 16

d. 32

4. Assertion(A): The multiplexer can be viewed as a function generator.

Reason(R): The multiplexer acts like a digitally controlled multi-position switch.

a. A is false but R is true

b. A is true but R is false

c. Both A and R are true, but R is not the correct explanation of A

d. Both A and R are true, and R is the correct explanation of A

5. A multiplexer has______.

a. One data output and number of select inputs

b. One data output and number of data inputs

c. One data output, a number of data inputs, and number of select inputs

d. One data input and number of data outputs

6. A multiplexer can be used as______.

a. 7-segement LED driver

b. Counter

c. Logic element

d. Flip-flop

7. To add two 4-bit numbers using a parallel adder circuit, we require_____.

a. 8-half adders

b. Neither (a) nor(b)

c. Either (a) or (b)

d. 4-full adders and 1-OR gate

8. The correction to be applied in decimal adder to the generated sum is____.

a. 01010

b. 01101

c. 00110

d. 00101

9. The gates required to build a half adder are:

a. EX-OR gate and OR gate

b.  EX-OR gate and NOR gate

c.  EX-OR gate and AND gate

d. Four NAND gate

10. The code where all successive numbers differ from their preceding number by a single bit is_____.

a. BCD code

b. Gray code

c. Excess-3 code

d. Binary code

11. A device which changes from serial data to parallel data is_______.

a. FLIP-FLOP

b. COUNTER

c. MULTIPLEXER

d. DEMULTIPLEXER

12. A device which converts BCD to Seven Segment is called_____.

a. Encoder

b. Decoder

c. Demultiplexer

d. Multiplexer

13. When the set of input data to an even parity generator is 0111, the output will be_____.

a. Depends on the previous input

b. 1

c. 0

d. Undefined

14. Compared to a parallel adder, a serial adder is______.

a. Faster, and requires more hardware

b. Slower, and Requires more hardware

c. Faster, and requires less hardware

d. Slower, and requires less hardware

15. In a 2-bit half adder, the sum and the carry bits are obtained, respectively, by the______.

a. NAND and OR gate

b. NAND and NOR gate 

c. NOr and EXCLUSIVE-OR gates

d. EXCLUSIVE-OR and AND gate

16. A 16-to-1 multiplexer can be used to______.

a. Convert a 4-bit serial input to a parallel output

b. Convert a 4-bit parallel input to a serial output

c. Convert a 16-bit serial input to a parallel output

d. Convert a 16-bit parallel input to a serial output