BPSC Tre 4.0 Computer Science MCQ | Multiplexer(MUX)_Digital Logic

 Multiplexer (MUX)_Digital Logic  MCQ

1. A multiplexer is also known as:

A. Data distributor
B. Data selector
C. Encoder
D. Decoder
Answer: B. Data selector
Explanation: A multiplexer selects one input from many and forwards it to a single output, hence called a data selector.

2. A multiplexer has:

A. One input and many outputs
B. Many inputs and many outputs
C. Many inputs and one output
D. One input and one output
Answer: C. Many inputs and one output
Explanation: MUX → Many-to-One device.

3. How many select lines are required for a 4-to-1 multiplexer?

A. 1
B. 2
C. 3
D. 4
Answer: B. 2
Explanation:
Number of select lines = log2(Number of inputs)

$${\log }_2(4)=2\mathrm{<br>}\mathrm{<br>}\mathrm{<br>}\mathrm{<br>}$$

4. A 2-to-1 multiplexer has:

A. 2 inputs, 1 output, 1 select line
B. 2 inputs, 1 output, 2 select lines
C. 1 input, 2 outputs, 1 select line
D. 1 input, 1 output, 2 select lines
Answer: A

5. Number of inputs in a multiplexer with 3 select lines is:

A. 6
B. 8
C. 16
D. 32
Answer: B. 8
Explanation:

$$\text{Inputs}=2^n=2^3=8\mathrm{<br>}\mathrm{<br>}$$

6. A multiplexer with 16 inputs will have how many select lines?

A. 2
B. 3
C. 4
D. 5
Answer: C. 4

7. Which logic gates are basically used to design a multiplexer?

A. AND only
B. OR only
C. NOT only
D. AND, OR, and NOT
Answer: D
Explanation:
MUX uses:

• NOT → for select line complements
• AND → to enable one input
• OR → to combine outputs

8. The output of a multiplexer depends on:

A. Only input lines
B. Only select lines
C. Both input and select lines
D. Clock signal
Answer: C

9. If select lines of a 4:1 MUX are S1S0 = 10, which input is selected?

A. I0
B. I1
C. I2
D. I3
Answer: C. I2
Explanation:
Binary value of 10 = 2, so I2 is selected.

10. A multiplexer is a:

A. Sequential circuit
B. Memory device
C. Combinational circuit
D. Arithmetic circuit
Answer: C

11. In a 2:1 multiplexer, when select line S = 0, output equals:

A. I1
B. I0
C. 0
D. 1
Answer: B. I0

12. Multiplexers are used for:

A. Data routing
B. Parallel to serial conversion
C. Implementing Boolean functions
D. All of the above
Answer: D

13. Which device performs the opposite function of a multiplexer?

A. Encoder
B. Decoder
C. Demultiplexer
D. Comparator
Answer: C

14. A multiplexer can be used as:

A. Logic gate
B. Data selector
C. Boolean function generator
D. All of the above
Answer: D

15. How many 2:1 multiplexers are required to design a 4:1 multiplexer?

A. 2
B. 3
C. 4
D. 5
Answer: B
Explanation:

• First level → 2 MUX    ( 4/2 )

• Second level → 1 MUX  ( 2/2 )
  Total = 2+1 = 3

16. Using multiplexers, which function is easiest to implement?

A. Arithmetic operations
B. Memory storage
C. Boolean expressions
D. Sequential logic
Answer: C

17. A 8:1 multiplexer has:

A. 8 select lines
B. 3 select lines
C. 4 select lines
D. 1 select line
Answer: B

18. If all select lines of a multiplexer are 0, which input is selected?

A. Highest input
B. Middle input
C. I0
D. Depends on MUX size
Answer: C

19. Which of the following statements is TRUE?

A. MUX is a memory device
B. MUX has multiple outputs
C. MUX is a combinational circuit
D. MUX requires clock
Answer: C

Q20. A multiplexer with n select lines has how many input lines?

A. n
B. 2n
C. 2ⁿ
D. n²
Answer: C

Q21. If select lines of a 4:1 MUX are S1S0 = 10, which input is selected?

A. I0
B. I1
C. I2
D. I3
Answer: C
Explanation:
Binary 10 = 2, so I2 is selected.

Q22. In a multiplexer, output depends on

A. Only inputs
B. Only select lines
C. Inputs and select lines
D. Clock pulse
Answer: C

Q23. A MUX always has

A. Equal inputs and outputs
B. Single output
C. Multiple outputs
D. No select line
Answer: B