A directory of Objective Type Questions covering all the Computer Science subjects. Here you can access and discuss Multiple choice questions and answers for various compitative exams and interviews.

11. Which of the following statements is wrong ?
a. Propagation delay is the time required for a gate to change its state
b. Noise immunity is the amount of noise which can be applied to the input of a gate without causing the gate to change state
c. Fan-in of a gate is always equal to fan-out of the same gate
d. Operating speed is the maximum frequency at which digital data can be applied to a gate
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Answer: (c).Fan-in of a gate is always equal to fan-out of the same gate

12. Which of the following expressions is not equivalent to X ' ?
a. X NAND X
b. X NOR X
c. X NAND 1
d. X NOR 1
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Answer: (d).X NOR 1

13. The EXCLUSIVE NOR gate is equivalent to which gate followed by an inverter ?
a. OR
b. AND
c. NAND
d. XOR
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Answer: (d).XOR

14. A one-to-four line demultiplexer is to be implemented using a memory. How many bits must each word have ?
a. 1 bit
b. 2 bits
c. 4 bits
d. 8 bits
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Answer: (a).1 bit

15. What logic function is produced by adding an inverter to the output of an AND gate ?
a. NAND
b. NOR
c. XOR
d. OR
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Answer: (a).NAND

16. Which of the following gates is known as coincidence detector ?
a. AND gate
b. OR gate
c. NOT gate
d. NAND gate
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Answer: (a).AND gate

17. Which table shows the logical state of a digital circuit output for every possible combination of logical states in the inputs ?
a. Function table
b. Truth table
c. Routing table
d. ASCII table
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Answer: (b).Truth table

18. A positive AND gate is also a negative
a. NAND gate
b. NOR gate
c. AND gate
d. OR gate
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Answer: (d).OR gate

19. A demultiplexer is used to
a. Route the data from single input to one of many outputs
b. Perform serial to parallel conversion
c. Both a & b
d. Select data from several inputs and route it to single output
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Answer: (c).Both a & b

20. An OR gate can be imagined as
a. Switches connected in series
b. Switches connected in parallel
c. MOS transistors connected in series
d. None of these
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Answer: (b).Switches connected in parallel

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