1. A multiplexer is a combinational circuit that is used to:
A. Select one of many inputs and send it to a single output
B. Perform arithmetic operations
C. Convert binary data into decimal
D. Store data
Answer: A. Select one of many inputs and send it to a single output
2. How many selection lines are required for a 4-to-1 multiplexer?
A. 1
B. 2
C. 3
D. 4
Answer: B. 2
3. A 2-to-1 multiplexer has how many data inputs?
A. 1
B. 2
C. 4
D. 8
Answer: B. 2
4. What is the primary function of a multiplexer?
A. Convert analog signals to digital
B. Send data to multiple destinations
C. Select one input line from many and forward it to the output
D. Store binary data
Answer: C. Select one input line from many and forward it to the output
5. A 8-to-1 multiplexer will require how many selection lines?
A. 3
B. 4
C. 5
D. 6
Answer: A. 3
6. The truth table of an n-to-1 multiplexer has how many rows?
A. 2n
B. n
C. 2^n
D. 2^n – 1
Answer: C. 2^n
7. In a 4-to-1 multiplexer, the logic equation for the output can be written as:
A. A = (S0 AND S1)
B. A = (S0 OR S1)
C. A = D0(S1′ S0′) + D1(S1′ S0) + D2(S1 S0′) + D3(S1 S0)
D. A = D0 + D1 + D2 + D3
Answer: C. A = D0(S1′ S0′) + D1(S1′ S0) + D2(S1 S0′) + D3(S1 S0)
8. Which of the following multiplexers has the maximum number of inputs?
A. 2-to-1
B. 4-to-1
C. 8-to-1
D. 16-to-1
Answer: D. 16-to-1
9. A multiplexer with ‘n’ selection lines can select between how many inputs?
A. n
B. 2n
C. 2^n
D. n^2
Answer: C. 2^n
10. The multiplexer used in data transmission systems to reduce the number of communication lines is known as a:
A. Data demux
B. Parallel converter
C. Time-division multiplexer
D. Frequency converter
Answer: C. Time-division multiplexer
11. A demultiplexer is a circuit that takes:
A. One input and selects one of many outputs
B. One input and sends it to all outputs
C. Many inputs and sends them to one output
D. None of the above
Answer: A. One input and selects one of many outputs
12. How many outputs does a 1-to-4 demultiplexer have?
A. 1
B. 2
C. 4
D. 8
Answer: C. 4
13. A 4-to-1 multiplexer and a 1-to-4 demultiplexer are closely related. Which of the following statements is true about them?
A. Both devices perform similar operations
B. The multiplexer selects one of many inputs, while the demultiplexer selects one of many outputs
C. A demultiplexer requires more selection lines than a multiplexer
D. Both have the same number of selection lines
Answer: B. The multiplexer selects one of many inputs, while the demultiplexer selects one of many outputs
14. A 3-to-8 demultiplexer has how many selection lines?
A. 1
B. 2
C. 3
D. 4
Answer: C. 3
15. The logic equation for a 1-to-4 demultiplexer output is:
A. Y0 = I(S2′ S1′ S0′)
B. Y0 = I(S1′ S0)
C. Y0 = I(S1 S0)
D. Y0 = I(S0′ S1)
Answer: A. Y0 = I(S2′ S1′ S0′)
16. What is the main application of a demultiplexer?
A. To combine multiple signals into one line
B. To split one input signal into multiple output signals
C. To store signals for later use
D. To perform arithmetic operations
Answer: B. To split one input signal into multiple output signals
17. How many selection lines are required for a 8-to-1 multiplexer?
A. 2
B. 3
C. 4
D. 5
Answer: B. 3
18. A demultiplexer with n selection lines can direct the input to how many outputs?
A. n
B. 2n
C. 2^n
D. 2^n – 1
Answer: C. 2^n
19. What is the main advantage of using a multiplexer in a communication system?
A. Reduces the number of data channels required
B. Increases the speed of transmission
C. Simplifies data encoding
D. Reduces the need for error checking
Answer: A. Reduces the number of data channels required
20. In a time-division multiplexing system, the role of the multiplexer is to:
A. Split the signal into multiple channels
B. Combine multiple signals into one channel
C. Convert analog to digital
D. Provide synchronization
Answer: B. Combine multiple signals into one channel