# Multiple choice question for engineering

## Set 1

1. What is a multiplexer?

a) It is a type of decoder which decodes several inputs and gives one output

b) A multiplexer is a device which converts many signals into one

c) It takes one input and results into many output

d) None of the Mentioned

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2. Which combinational circuit is renowned for selecting a single input from multiple inputs & directing the binary information to output line?

a) Data Selector

b) Data distributor

c) Both data selector and data distributor

d) None of the Mentioned

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3. It is possible for an enable or strobe input to undergo an expansion of two or more MUX ICs to the digital multiplexer with the proficiency of large number of

a) Inputs

b) Outputs

c) Selection lines

d) All of the Mentioned

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4. Which is the major functioning responsibility of the multiplexing combinational circuit?

a) Decoding the binary information

b) Generation of all minterms in an output function with OR-gate

c) Generation of selected path between multiple sources and a single destination

d) All of the Mentioned

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5. What is the function of an enable input on a multiplexer chip?

a) To apply Vcc

b) To connect ground

c) To active the entire chip

d) To active one half of the chip

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6. One multiplexer can take the place of

a) Several SSI logic gates

b) Combinational logic circuits

c) Several Ex-NOR gates

d) Several SSI logic gates or combinational logic circuits

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7. A digital multiplexer is a combinational circuit that selects

a) One digital information from several sources and transmits the selected one

b) Many digital information and convert them into one

c) Many decimal inputs and transmits the selected information

d) None of the Mentioned

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8. In a multiplexer, the selection of a particular input line is controlled by

a) Data controller

b) Selected lines

c) Logic gates

d) Both data controller and selected lines

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9. If the number of n selected input lines is equal to 2^m then it requires _____ select lines.

a) 2

b) m

c) n

d) None of the Mentioned

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10. How many select lines would be required for an 8-line-to-1-line multiplexer?

a) 2

b) 4

c) 8

d) 3

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11. A basic multiplexer principle can be demonstrated through the use of a

a) Single-pole relay

b) DPDT switch

c) Rotary switch

d) Linear stepper

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12. How many NOT gates are required for the construction of a 4-to-1 multiplexer?

a) 3

b) 4

c) 2

d) 5

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13. In the given 4-to-1 multiplexer, if c1 = 0 and c0 = 1 then the output M is

a) X0

b) X1

c) X2

d) X3

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14. The enable input is also known as

a) Select input

b) Decoded input

c) Strobe

d) Sink

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## Set 2

1. Any negative number is recognized by its

a) MSB

b) LSB

c) Bits

d) Nibble

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2. The parameter through which 16 distinct values can be represented is known as:

a) Bit

b) Byte

c) Nibble

d) Word

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3. If the decimal number is a fraction then its binary equivalent is obtained by ________ the number continuously by 2.

a) Dividing

b) Multiplying

c) Adding

d) Subtracting

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4. The representation of decimal number 532.86 in the form of decimal is

a) 532.65

b) 532.68

c) 531.67

d) 531.68

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^{2}+ 3 * 10

^{1}+ 2 * 10

^{0}+ 8 * 10^-1 +6 * 10^-2 = 532.68

5. The binary equivalent of (1011.011)10 is equal to

a) 11.375

b) 10.123

c) 11.175

d) 9.234

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^{3}+ 0 * 2

^{2}+ 1 * 2

^{1}+ 0 * 2^-1 +1 * 2^-2 + 1 * 2^-3 = 11.375 Hence, (1011.011)10 = 11.375

6. An important drawback of binary system is

a) It requires very large string of 1’s and 0’s to represent a decimal number

b) It requires sparingly small string of 1’s and 0’s to represent a decimal number

c) It requires large string of 1’s and small string of 0’s to represent a decimal number

d) None of the Mentioned

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7. The octal number 645 in power of 8 is equal to

a) 450

b) 451

c) 421

d) 501

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^{2}+ 4 * 8

^{1}+ 5 * 8

^{0}= 421

8. The two digits hexadecimal number which has largest value is ___ which corresponds to _____

a) FE, 255 decimal

b) FF, 254 decimal

c) FF, 255 decimal

d) EF, 245 decimal

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^{1}+ 15 * 16

^{0}= 255 (since, F = 15)

9. Representation of hexadecimal number 6DE in the power of 16 is as:

a) 6 * 16^{2} + 13 * 16^{1} + 14 * 16^{0}

b) 6 * 16^{2} + 12 * 16^{1} + 13 * 16^{0}

c) 6 * 16^{2} + 11 * 16^{1} + 14 * 16^{0}

d) 6 * 16^{2} + 14 * 16^{1} + 15 * 16^{0}

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^{2}+ 13 * 16

^{1}+ 14 * 16

^{0}.

10. The quantity of double word is

a) 16 bits

b) 32 bits

c) 64 bits

d) 8 bits

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## Set 3

1. The given hex number (1E.53)16 is equivalent to

a) (35.68)8

b) (35.24)8

c) (34.34)8

d) (35.59)8

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2. The octal number (651.124)8 is equivalent to

a) (1A9.260)16

b) (1B0.160)16

c) (1A8.023)16

d) (1B0.289)16

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3. The decimal equivalent of (LM17) is given by

a) 491

b) 499

c) 497

d) 498

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^{0}+ 3 * 5

^{1}+ M * 5

^{2}+ L * 5

^{3}= 1 * 5

^{0}+ 3 * 5

^{1}+ 4 * 5

^{2}+ 3 * 5

^{3}(L=3, M=4) = 491.00

4. Convert hexadecimal to binary: (1E2H) = ?

a) 480

b) 483

c) 482

d) 484

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^{2}+ E * 16

^{1}+ 2 * 16

^{0}= 256 + 224 + 2 = 482

5. (170)10 is equivalent to

a) (FD)16

b) (DF)16

c) (AA)16

d) (AF)16

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6. Convert in to decimal: (214)8 = ?

a) (140)10

b) (141)10

c) (142)10

d) (130)10

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^{2}+ 1 * 8

^{1}+ 4 * 8

^{0}= 128.0 + 8.0 + 4 = (140)10

7. Convert (0.345)10 in to an octal number.

a) (0.1605)8

b) (0.2605)8

c) (0.1945)8

d) (0.2404)8

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8. Convert from binary to decimal: (01011.1011)2 = ?

a) (11.6875)10

b) (11.5874)10

c) (10.9876)10

d) (10.7893)10

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^{4}+ 1 * 2

^{3}+ 0 * 2

^{2}+ 1 * 2

^{1}+ 1 * 2

^{0}= 11 (1011)2 = 1 * 2

^{-1}+ 0 * 2

^{-2}+ 1 * 2

^{-3}+ 1 * 2

^{-4}= 0.6875 So, (01011.1011)2 = (11.6875)10

9. Octal to binary conversion: (24)8 = ?

a) (111101)2

b) (010100)2

c) (111100)2

d) (101010)2

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10. Convert binary to octal: (110110001010)2 = ?

a) (5512)8

b) (6612)8

c) (4532)8

d) (6745)8

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## Set 4

1. How many outputs are present in a BCD decoder?

a) 4

b) 5

c) 15

d) 10

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2. Which digital system translates coded characters into a more useful form?

a) Encoder

b) Display

c) Counter

d) Decoder

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3. What control signals may be necessary to operate a 1-line-to-16 line decoder?

a) Flasher circuit control signal

b) A LOW on all gate enable inputs

c) Input from a hexadecimal counter

d) A HIGH on all gate enable circuits

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4. How many inputs are required for a 1-of-10 BCD decoder?

a) 4

b) 8

c) 10

d) 2

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5. A BCD decoder will have how many rows in its truth table?

a) 3

b) 9

c) 8

d) 10

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6. How many possible outputs would a decoder have with a 6-bit binary input?

a) 32

b) 64

c) 128

d) 16

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7. One way to convert BCD to binary using the hardware approach is:

a) By using MSI IC circuits

b) By using a keyboard encoder

c) By using an ALU

d) By using UART

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8. How many inputs are required for a 1-of-16 decoder?

a) 2

b) 16

c) 8

d) 4

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9. A truth table with output columns numbered 0–15 may be for which type of decoder IC?

a) Hexadecimal 1-of-16

b) Dual octal outputs

c) Binary-to-hexadecimal

d) Hexadecimal-to-binary

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10. How can the active condition (HIGH or LOW) or the decoder output be determined from the logic symbol?

a) A bubble indicates active-HIGH

b) A bubble indicates active-LOW

c) A square indicates active-HIGH

d) A square indicates active-LOW

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## Set 5

1. The basic building blocks of the arithmetic unit in a digital computers are

a) Subtractors

b) Adders

c) Multiplexer

d) None of the Mentioned

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2. A digital system consists of _____ types of circuits.

a) 2

b) 3

c) 4

d) 5

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3. In a combinational circuit, the output at any time depends only on the _______ at that time.

a) Voltage

b) Intermediate values

c) Input values

d) None of the Mentioned

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4. In a sequential circuit, the output at any time depends only on the input values at that time.

a) Past output values

b) Intermediate values

c) Present input values

d) None of the Mentioned

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5. Procedure for the design of combinational circuits are:

A. From the word description of the problem, identify the inputs and outputs and draw a block diagram.

B. Draw the truth table such that it completely describes the operation of the circuit for different combinations of inputs.

C. Simplify the switching expression(s) for the output(s).

D. Implement the simplified expression using logic gates.

E. Write down the switching expression(s) for the output(s).

a) B, C, D, E, A

b) A, D, E, B, C

c) A, B, E, C, D

d) None of the Mentioned

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6. All logic operations can be obtained by means of

a) AND and NAND operations

b) OR and NOR operations

c) OR and NOT operations

d) AND, OR and NOT operations

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7. The design of an ALU is based on

a) Sequential logic

b) Combinational logic

c) Multiplexing

d) None of the Mentioned

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8. If the two numbers are unsigned, the bit conditions of interest are the ______ carry and a possible _____ result.

a) Input, zero

b) Output, one

c) Input, one

d) Output, zero

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9. If the two numbers include a sign bit in the highest order position, the bit conditions of interest are the sign of the result, a zero indication and

a) An underflow condition

b) A neutral condition

c) An overflow condition

d) None of the Mentioned

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10. The flag bits in an ALU is defined as

a) The total number of registers

b) The status bit conditions

c) The total number of control lines

d) All of the Mentioned