1. Digital electronics deals primarily with signals that are:
A. Continuous
B. Analog
C. Discrete
D. Mixed
Answer: C. Discrete
2. A binary digit is also known as:
A. Byte
B. Bit
C. Nibble
D. Word
Answer: B. Bit
3. The two possible states in a binary system are:
A. 0 and 1
B. 1 and 2
C. High and low
D. True and false
Answer: A. 0 and 1
4. The value of the binary number 1101 is:
A. 13
B. 12
C. 14
D. 15
Answer: A. 13
5. Which of the following is used to convert binary numbers to decimal?
A. Binary addition
B. Decimal to binary conversion
C. Binary multiplication
D. None of the above
Answer: D. None of the above (Decimal to binary conversion involves converting binary numbers to decimal)
6. Which of the following is the correct logic operation for an AND gate?
A. Output is 1 when all inputs are 1
B. Output is 1 when at least one input is 1
C. Output is 0 when all inputs are 1
D. Output is 1 when no inputs are 1
Answer: A. Output is 1 when all inputs are 1
7. The symbol for a NOT gate is:
A. A triangle with a dot
B. A triangle with a small circle
C. A circle
D. A square
Answer: B. A triangle with a small circle
8. Which gate is a combination of an AND gate and a NOT gate?
A. NAND
B. NOR
C. XOR
D. XNOR
Answer: A. NAND
9. The XOR (exclusive OR) gate outputs 1 when:
A. The inputs are the same
B. The inputs are different
C. One input is 1 and the other is 0
D. All inputs are 0
Answer: B. The inputs are different
10. The truth table for a NOR gate is the opposite of the:
A. AND gate
B. OR gate
C. XOR gate
D. NAND gate
Answer: B. OR gate
11. A multiplexer (MUX) is used to:
A. Perform binary addition
B. Select one of many inputs
C. Store a binary number
D. Convert binary to decimal
Answer: B. Select one of many inputs
12. A demultiplexer (DEMUX) is used to:
A. Convert a binary number to a decimal
B. Split one input into multiple outputs
C. Perform binary subtraction
D. Combine multiple inputs into one output
Answer: B. Split one input into multiple outputs
13. A full adder circuit can add:
A. Two single-bit binary numbers
B. Two binary numbers with carry input
C. A binary number and a decimal number
D. A binary number and a hexadecimal number
Answer: B. Two binary numbers with carry input
14. A half adder is used to add:
A. Two single-bit binary numbers without a carry input
B. Two multi-bit binary numbers
C. Two numbers with a carry output
D. A binary and decimal number
Answer: A. Two single-bit binary numbers without a carry input
15. A priority encoder produces a binary code corresponding to:
A. The highest order bit
B. The lowest order bit
C. The combination of all bits
D. The highest priority input
Answer: D. The highest priority input
16. A flip-flop is a:
A. Combinational circuit
B. Digital memory element
C. Power supply circuit
D. Type of amplifier
Answer: B. Digital memory element
17. The most common type of flip-flop used in digital circuits is:
A. RS flip-flop
B. JK flip-flop
C. D flip-flop
D. T flip-flop
Answer: C. D flip-flop
18. A JK flip-flop is a type of flip-flop that:
A. Has a reset and set input
B. Can toggle its output
C. Stores a single bit of data
D. Has only one input
Answer: B. Can toggle its output
19. A T flip-flop is derived from which type of flip-flop?
A. D flip-flop
B. RS flip-flop
C. JK flip-flop
D. None of the above
Answer: C. JK flip-flop
20. A counter is a sequential circuit that is used to:
A. Perform binary addition
B. Store and transmit data
C. Count pulses or events
D. Add multi-bit binary numbers
Answer: C. Count pulses or events
21. The Gray code is a binary number system in which:
A. Only one bit changes at a time
B. All bits change simultaneously
C. The least significant bit is constant
D. Only even numbers are used
Answer: A. Only one bit changes at a time
22. In BCD (Binary Coded Decimal), each decimal digit is represented by:
A. A 4-bit binary code
B. A 3-bit binary code
C. A 5-bit binary code
D. An 8-bit binary code
Answer: A. A 4-bit binary code
23. In the hexadecimal system, the number ‘A’ represents:
A. 9
B. 10
C. 11
D. 12
Answer: B. 10
24. The binary equivalent of the decimal number 25 is:
A. 10111
B. 11001
C. 11010
D. 10101
Answer: B. 11001
25. The Excess-3 (XS-3) code is a binary code in which each decimal digit is represented by:
A. Its binary equivalent plus 3
B. Its binary equivalent minus 3
C. A 4-bit binary value
D. A 5-bit binary value
Answer: A. Its binary equivalent plus 3
26. A shift register is used to:
A. Store multiple bits of data and shift them in a specified direction
B. Perform arithmetic operations
C. Encode and decode data
D. Convert digital signals to analog
Answer: A. Store multiple bits of data and shift them in a specified direction
27. A serial adder performs addition by:
A. Adding one bit at a time from two numbers
B. Adding all bits simultaneously
C. Subtracting bits from the two numbers
D. Storing results in memory
Answer: A. Adding one bit at a time from two numbers
28. A Digital-to-Analog Converter (DAC) is used to:
A. Convert an analog signal into a digital signal
B. Convert digital data into a proportional analog voltage or current
C. Add two digital signals
D. Store digital data
Answer: B. Convert digital data into a proportional analog voltage or current
29. A register in a digital system is used to:
A. Perform arithmetic operations
B. Temporarily store binary data
C. Convert signals
D. Perform data encryption
Answer: B. Temporarily store binary data
30. A multiplexer (MUX) allows for:
A. Parallel-to-serial conversion
B. Selection of one output from multiple inputs
C. Input signal amplification
D. Analog signal encoding
Answer: B. Selection of one output from multiple inputs