Explore topic-wise MCQs in Digital Electronics.

This section includes 194 Mcqs, each offering curated multiple-choice questions to sharpen your Digital Electronics knowledge and support exam preparation. Choose a topic below to get started.

101.

Binary multiplication is like decimal multiplication except you deal only with 1s and 0s.

A. 1
B.
Answer» B.
102.

The solution to the binary problem 0101 + 1111 is 10100.

A. 1
B.
Answer» B.
103.

The binary subtraction 1 – 1 = ________.

A. difference = 0borrow = 0
B. difference = 1borrow = 0
C. difference = 1borrow = 1
D. difference = 0borrow = 1
Answer» B. difference = 1borrow = 0
104.

Solve this BCD problem: 0100 + 0110 =

A. 00010000BCD
B. 00010111BCD
C. 00001011BCD
D. 00010011BCD
Answer» B. 00010111BCD
105.

What is the correct output of the adder in the given figure, with the outputs in the order:

A. 10111
B. 11101
C. 1101
D. 10011
Answer» B. 11101
106.

What is the most important operation in binary-coded decimal (BCD) arithmetic?

A. addition
B. subtraction
C. multiplication
D. division
Answer» B. subtraction
107.

When multiplying 13 √ó 11 in binary, what is the third partial product?

A. 1011
B. 0
C. 100000
D. 100001
Answer» C. 100000
108.

Using 4-bit adders to create a 1See Section 6-bit adder:

A. requires 16 adders.
B. requires 4 adders.
C. requires the carry-out of the less significant adder to be connected to the carry-in of the next significant adder.
D. requires 4 adders and the connection of the carry out of the less significant adder to the carry-in of the next significant adder.
Answer» E.
109.

The summing outputs of a half- or full-adder are designated by which Greek symbol?

A. omega
B. theta
C. lambda
D. sigma
Answer» E.
110.

The carry propagation delay in full-adder circuits:

A. is normally not a consideration because the delays are usually in the nanosecond range.
B. decreases in a direct ratio to the total number of FA stages.
C. is cumulative for each stage and limits the speed at which arithmetic operations are performed.
D. increases in a direct ratio to the total number of FA stages but is not a factor in limiting the speed of arithmetic operations.
Answer» D. increases in a direct ratio to the total number of FA stages but is not a factor in limiting the speed of arithmetic operations.
111.

Convert each of the decimal numbers to 8-bit two's-complement form and then perform subtraction by taking the two's-complement and adding.

A. 0001  0011
B. 0000  1110
C. 0010  1110
D. 1110  0000
Answer» C. 0010¬†¬†1110
112.

111010002 is the 2's-complement representation of –24.

A. 1
B.
C. 1
D.
Answer» C. 1
113.

The truth table for a full adder is shown below. What are the values of X, Y, and Z?

A. X = 0, Y = 1, Z = 1
B. X = 1, Y = 1, Z = 1
C. X = 1, Y = 0, Z = 1
D. X = 0, Y = 0, Z = 1
Answer» C. X = 1, Y = 0, Z = 1
114.

The selector inputs to an arithmetic/logic unit (ALU) determine the:

A. selection of the IC
B. arithmetic or logic function
C. data word selection
D. clock frequency to be used
Answer» C. data word selection
115.

Determine the two's-complement of each binary number.00110        00011        11101

A. 11001    11100    00010
B. 00111    00010    00010
C. 00110    00011    11101
D. 11010    11101    00011
Answer» E.
116.

Half-adders can be combined to form a full-adder with no additional gates.

A. 1
B.
Answer» C.
117.

The two's-complement method is used in computer systems that perform arithmetic.

A. 1
B.
C. 1
D.
Answer» B.
118.

The binary adder circuit is designed to add ________ binary number(s) at a time.

A. 1
B. 3
C. 2
D. 5
Answer» D. 5
119.

A full adder has a carry-in.

A. 1
B.
Answer» B.
120.

What is the difference between a full-adder and a half-adder?

A. Half-adder has a carry-in.
B. Full-adder has a carry-in.
C. Half-adder does not have a carry-out.
D. Full-adder does not have a carry-out.
Answer» C. Half-adder does not have a carry-out.
121.

34FC + AD31 = ________.

A. E22D
B. E31D
C. E21D
D. E42D
Answer» B. E31D
122.

The range of positive numbers when using an eight-bit two's-complement system is:

A. 0 to 64
B. 0 to 100
C. 0 to 127
D. 0 to 256
Answer» D. 0 to 256
123.

What is the major difference between half-adders and full-adders?

A. Nothing basically; full-adders are made up of two half-adders.
B. Full adders can handle double-digit numbers.
C. Full adders have a carry input capability.
D. Half adders can handle only single-digit numbers.
Answer» D. Half adders can handle only single-digit numbers.
124.

Which of the following is the primary advantage of using binary-coded decimal (BCD) instead of straight binary coding?

A. Fewer bits are required to represent a decimal number with the BCD code.
B. BCD codes are easily converted from decimal.
C. the relative ease of converting to and from decimal
D. BCD codes are easily converted to straight binary codes.
Answer» D. BCD codes are easily converted to straight binary codes.
125.

Convert each of the following signed binary numbers (two's-complement) to a signed decimal number.00000101        11111100        11111000

A. –5    +4    +8
B. +5    –4    –8
C. –5    +252    +248
D. +5    –252    –248
Answer» C. ‚Äì5¬†¬†¬†¬†+252¬†¬†¬†¬†+248
126.

The solution to the binary problem 00110110 – 00011111 is 00011000.

A. 1
B.
Answer» C.
127.

The BCD addition of 910 and 710 will give initial code groups of 1001 + 0111. Addition of these groups generates a carry to the next higher position. The correct solution to this problem would be to:

A. ignore the lowest order code group because 0000 is a valid code group and prefix the carry with three zeros
B. add 0110 to both code groups to validate the carry from the lowest order code group
C. disregard the carry and add 0110 to the lowest order code group
D. add 0110 to the lowest order code group because a carry was generated and then prefix the carry with three zeros
Answer» E.
128.

How many basic binary subtraction operations are possible?

A. 4
B. 3
C. 2
D. 1
Answer» B. 3
129.

What are the two types of basic adder circuits?

A. sum and carry
B. half-adder and full-adder
C. asynchronous and synchronous
D. one- and two's-complement
Answer» C. asynchronous and synchronous
130.

The 2's-complement system is to be used to add the signed binary numbers 11110010 and 11110011. Determine, in decimal, the sign and value of each number and their sum.

A. –113 and –114, –227
B. –14 and –13, –27
C. –11 and –16, –27
D. –27 and –13, –40
Answer» C. ‚Äì11 and ‚Äì16, ‚Äì27
131.

An 8-bit register may provide storage for two's-complement codes within which decimal range?

A. +128 to –128
B. –128 to +127
C. +128 to –127
D. +127 to –127
Answer» C. +128 to ‚Äì127
132.

Subtract the following binary numbers. 0101 1000   1010 0011   1101 1110 –0010 0011   –0011 1000   –0101 0111

A. 0011  0100    0110  1010    1000  0110
B. 0011  0101    0110  1011    1000  0111
C. 0011  0101    0110  1010    1000  0111
D. 0011  0101    0110  1010    1000  0110
Answer» C. 0011¬†¬†0101¬†¬†¬†¬†0110¬†¬†1010¬†¬†¬†¬†1000¬†¬†0111
133.

A binary sum is made up of only 1s and 0s.

A. 1
B.
C. 1
D.
Answer» B.
134.

Perform the following hex subtraction: ACE16 – 99916 =

A. 23516
B. 13516
C. 3516
D. 33516
Answer» C. 3516
135.

An input to the mode pin of an arithmetic/logic unit (ALU) determines if the function will be:

A. one's-complemented
B. arithmetic or logic
C. positive or negative
D. with or without carry
Answer» C. positive or negative
136.

The two's-complement system is to be used to add the signed numbers 11110010 and 11110011. Determine, in decimal, the sign and value of each number and their sum.

A. –14 and –13, –27
B. –113 and –114, 227
C. –27 and –13, 40
D. –11 and –16, –27
Answer» B. ‚Äì113 and ‚Äì114, 227
137.

The binary adder circuit is designed to add ________ binary numbers at the same time.

A. 2
B. 4
C. 6
D. 8
Answer» B. 4
138.

When the 2's-complement system is used, the number to be subtracted is changed to its 2's complement and then added to the minuend.

A. 1
B.
C. 1
D.
Answer» B.
139.

Solve this binary problem: 01011000 √∑ 00001011 = ________.

A. 1010
B. 110
C. 1000
D. 1110
Answer» D. 1110
140.

Solve this binary problem: 01000110 √∑ 00001010 =

A. 111
B. 10011
C. 1001
D. 11
Answer» B. 10011
141.

Convert each of the signed decimal numbers to an 8-bit signed binary number (two's-complement).+7        –3        –12

A. 0000  0111    1111  1101    1111  0100
B. 1000  0111    0111  1101    0111  0100
C. 0000  0111    0000  0011    0000  1100
D. 0000  0111    1000  0011    1000  1100
Answer» B. 1000¬†¬†0111¬†¬†¬†¬†0111¬†¬†1101¬†¬†¬†¬†0111¬†¬†0100
142.

Solve this binary problem:

A. 1001
B. 110
C. 111
D. 101
Answer» D. 101
143.

When performing subtraction by addition in the 2's-complement system:

A. the minuend and the subtrahend are both changed to the 2's-complement.
B. the minuend is changed to 2's-complement and the subtrahend is left in its original form.
C. the minuend is left in its original form and the subtrahend is changed to its 2's-complement.
D. the minuend and subtrahend are both left in their original form.
Answer» D. the minuend and subtrahend are both left in their original form.
144.

Binary subtraction of a decimal 15 from 43 will utilize which two's complement?

A. 101011
B. 110000
C. 11100
D. 110001
Answer» E.
145.

Add the following binary numbers. 0010 0110   0011 1011   0011 1100 +0101 0101   +0001 1110   +0001 1111

A. 0111 1011    0100  0001    0101  1011
B. 0111 1011    0101  1001    0101  1011
C. 0111 0111    0101  1001    0101  1011
D. 0111 0111    0100  0001    0101  1011
Answer» C. 0111 0111¬†¬†¬†¬†0101¬†¬†1001¬†¬†¬†¬†0101¬†¬†1011
146.

What is wrong, if anything, with the circuit in the given figure based on the logic analyzer display accompanying the circuit?

A. The CO terminal is shorted to ground.
B. The S1 output is shorted to Vcc.
C. The P1 input is not being added into the total.
D. Nothing is wrong; the circuit is functioning correctly.
Answer» D. Nothing is wrong; the circuit is functioning correctly.
147.

BCD arithmetic is performed using base 10 numbers.

A. 1
B.
Answer» C.
148.

Find the 2's complement of –1101102.

A. 1101002
B. 1010102
C. 10012
D. 10102
Answer» E.
149.

Add the following hex numbers: 011016 + 1001016

A. 1012016
B. 1002016
C. 1112016
D. 12016
Answer» B. 1002016
150.

How many BCD adders would be required to add the numbers 97310 + 3910?

A. 3
B. 4
C. 5
D. 6
Answer» B. 4