Multiplexers and demultiplexers MCQs January 8, 2026November 19, 2024 by u930973931_answers 20 min Score: 0 Attempted: 0/20 Subscribe 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 2. How many selection lines are required for a 4-to-1 multiplexer? (A) 1 (B) 2 (C) 3 (D) 4 3. A 2-to-1 multiplexer has how many data inputs? (A) 1 (B) 8 (C) 4 (D) 2 4. The primary function of a multiplexer is: (A) Convert analog signals to digital (B) Send data to multiple destinations (C) Store binary data (D) Select one input line from many and forward it to the output 5. An 8-to-1 multiplexer requires how many selection lines? (A) 5 (B) 4 (C) 3 (D) 6 6. The truth table of an n-to-1 multiplexer has how many rows? (A) 2n (B) n (C) 2^n ā 1 (D) 2^n 7. In a 4-to-1 multiplexer, the logic equation for the output is: (A) A = (S0 AND S1) (B) A = D0(S1ā² S0ā²) + D1(S1ā² S0) + D2(S1 S0ā²) + D3(S1 S0) (C) A = (S0 OR S1) (D) A = D0 + D1 + D2 + D3 8. Which multiplexer has the maximum number of inputs? (A) 2-to-1 (B) 16-to-1 (C) 8-to-1 (D) 4-to-1 9. A multiplexer with ānā selection lines can select between how many inputs? (A) n (B) 2n (C) 2^n (D) n^2 10. The multiplexer used in data transmission systems to reduce the number of communication lines is known as: (A) Data demux (B) Time-division multiplexer (C) Parallel converter (D) Frequency converter 11. A demultiplexer is a circuit that takes: (A) None of the above (B) One input and sends it to all outputs (C) Many inputs and sends them to one output (D) One input and selects one of many outputs 12. How many outputs does a 1-to-4 demultiplexer have? (A) 1 (B) 4 (C) 2 (D) 8 13. A 4-to-1 multiplexer and a 1-to-4 demultiplexer are related. Which is true? (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 14. A 3-to-8 demultiplexer has how many selection lines? (A) 3 (B) 2 (C) 1 (D) 4 15. The logic equation for a 1-to-4 demultiplexer output is: (A) Y0 = I(S1ā² S0) (B) Y0 = I(S2ā² S1ā² S0ā²) (C) Y0 = I(S1 S0) (D) Y0 = I(S0ā² S1) 16. Main application of a demultiplexer: (A) To combine multiple signals into one line (B) To store signals for later use (C) To split one input signal into multiple output signals (D) To perform arithmetic operations 17. How many selection lines are required for an 8-to-1 multiplexer? (A) 3 (B) 2 (C) 4 (D) 5 18. A demultiplexer with n selection lines can direct the input to how many outputs? (A) n (B) 2^n (C) 2n (D) 2^n ā 1 19. Main advantage of using a multiplexer in a communication system: (A) Reduces the need for error checking (B) Increases the speed of transmission (C) Simplifies data encoding (D) 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) Convert analog to digital (C) Combine multiple signals into one channel (D) Provide synchronization