Digital Logic MCQ Quiz - Objective Question with Answer for Digital Logic - Download Free PDF
Last updated on Jun 23, 2025
Latest Digital Logic MCQ Objective Questions
Digital Logic Question 1:
147 in base 10 when converted to hexadecimal system will be:
Answer (Detailed Solution Below)
Digital Logic Question 1 Detailed Solution
Answer: Option 3
Explanation:
Step 1: first we convert 147 to the Binary number system.
(147)10 = (10010011)2
Step 2: Now we group 4 bits to convert the Hexadecimal number system.
1001 0011
≡ (93)16
Digital Logic Question 2:
Which of the following codes is also known as reflected binary code?
Answer (Detailed Solution Below)
Digital Logic Question 2 Detailed Solution
The correct answer is Gray code.
Key Points
- The Gray code, also referred to as the reflected binary code, is a binary numeral system in which two consecutive numbers differ in only one bit. The unique property of Gray code is that each transition from one value to the next value involves changing only one bit.
- This system was invented by Frank Gray at Bell Labs to prevent spurious output from electromechanical switches. For instance, while switching from one position to another in standard binary code, there is a risk that switches will change at different times leading to invalid numbers, but with Gray code, since only one bit changes at a time, such misinterpretations are avoided.
- So, Gray code is also known as reflected binary code because the sequence of binary values reflects it about its midpoint. For example:
- Binary: 000, 001, 010, 011, 100, 101, 110, 111
- If we reflect this sequence, i.e., reverse it, we get:111, 110, 101, 100, 011, 010, 001, 000
-
Now let's take the first half of the original sequence and the first half of the reflected sequence.
-
By inverting the bits in the second half, we get the sequence of Gray codes: 000, 001, 011, 010, 110, 111, 101, 100
So, every binary number has a unique Gray code, and vice versa, attributing to why the term "reflected binary code" is used to describe the Gray code.
Digital Logic Question 3:
The decimal equivalent of a binary number 1001110 is:
Answer (Detailed Solution Below)
Digital Logic Question 3 Detailed Solution
Convert binary to decimal :-
- For binary number with n digits:
- dn-1 ... d3 d2 d1 d0
- The decimal number is equal to the sum of binary digits (dn) times their power of 2 (2n):
- decimal = d0×20 + d1×21 + d2×22 + ...
Calculation:
Decimal equivalent of binary number 1001110 :-
= 1 × 26 + 0 x 25 + 0 x 24 + 1 x 23 + 1 x 22 + 1 x 21 + 0 x 20
= 64 + 0 + 0 + 8 + 4 + 2 + 0 = 78
Digital Logic Question 4:
The binary representation of 129.25 is _____ .
Answer (Detailed Solution Below)
Digital Logic Question 4 Detailed Solution
Binary to decimal conversion →
(129)10 = (10000001)2
0.25 → 0.25 × 2 = 0.5
0.5 × 2 = 1
(0.25)10 = (.01)2
(129.25)10 = (10000001.01)2
Digital Logic Question 5:
2's complement of (1000)2 is
Answer (Detailed Solution Below)
Digital Logic Question 5 Detailed Solution
2's Complement - It is a type of mathematical and logical (binary) representation that helps in representing signed numbers and performing arithmetic operations such as subtraction, addition, etc.
To perform 2's complement of (1000)2 we will perform the following steps -
- We will perform 1's complement on (1000)2 by flipping 1s to 0s and 0s to 1s.
(1000)2 ===> (0111)2 - Now we will add 1 to the resultant value, that is, (0111)2.
(0111)2 + (1)2 ===> (1000)2 - Hence, we get (1000)2 back after 2's complement.
Top Digital Logic MCQ Objective Questions
Binary number 101110110 is equal to decimal number _______.
Answer (Detailed Solution Below)
Digital Logic Question 6 Detailed Solution
Download Solution PDF- The correct answer is option 3, i.e., 374.
- Binary number 101110110 is equal to decimal number 374.
- Following method can be used to convert Binary number to Decimal number:
- (101110110)2 = (1 x 28) + (0 x 27) + (1 x 26) + (1 x 25) + (1 x 24) + (0 x 23) + (1 x 22) + (1 x 21) + (0 x 20)
- (101110110)2 = 256 + 0 + 64 + 32 + 16 + 0 + 4 + 2 + 0
- (101110110)2 = 374
One megabyte In base 2 (binary) Is equivalent to .
Answer (Detailed Solution Below)
Digital Logic Question 7 Detailed Solution
Download Solution PDFThe correct answer is 220 bytes.
Key Points
- 1 Megabyte is equal to 1000000 bytes (decimal).
- 1 MB = 106 B in base 10 (SI).
- 1 Megabyte is equal to 1048576 bytes (binary).
- 1 MB = 220 B in base 2.
- Byte is the basic unit of digital information transmission and storage, used extensively in information technology, digital technology, and other related fields. It is one of the smallest units of memory in computer technology, as well as one of the most basic data measurement units in programming.
- The earliest computers were made with the processor supporting 1 byte commands, because in 1 byte you can send 256 commands. 1 byte consists of 8 bits,
- Megabyte (MB) is a unit of transferred or stored digital information, which is extensively used in information and computer technology.
- In SI, one megabyte is equal to 1,000,000 bytes. At the same time, practically 1 megabyte is used as 220 B, which means 1,048,576 bytes.
Binary 110110101 is equal to decimal ________.
Answer (Detailed Solution Below)
Digital Logic Question 8 Detailed Solution
Download Solution PDFBinary 110110101 is equal to decimal 437
Calculation:
1 1 0 1 1 0 1 0 1
From rightmost first column as follows
=> (20 * 1) + (21 * 0) + (22 * 1) + (23 * 0) + (24 * 1) + (25 * 1) + (26 * 0) + (27 * 1) + (28 * 1)
=> (1) + (0) + (4) + (0) + (16) + (32) + (0) + (128) + (256)
Decimal value =>437
Convert the hexadecimal number C6 to binary number.
Answer (Detailed Solution Below)
Digital Logic Question 9 Detailed Solution
Download Solution PDFThe correct answer is 11000110
Key Points
- To convert the hexadecimal number C6 to a binary number, you can convert each hexadecimal digit to its 4-bit binary representation.
- C in hexadecimal is 12 in decimal, which is 1100 in binary.
- 6 in hexadecimal is 6 in decimal, which is 0110 in binary.
- So, the binary representation of C6 is 11000110.
Additional InformationHere are the decimal numbers 1 to 15 represented in both hexadecimal and binary forms:
- Decimal 1: Hexadecimal 1, Binary 0001
- Decimal 2: Hexadecimal 2, Binary 0010
- Decimal 3: Hexadecimal 3, Binary 0011
- Decimal 4: Hexadecimal 4, Binary 0100
- Decimal 5: Hexadecimal 5, Binary 0101
- Decimal 6: Hexadecimal 6, Binary 0110
- Decimal 7: Hexadecimal 7, Binary 0111
- Decimal 8: Hexadecimal 8, Binary 1000
- Decimal 9: Hexadecimal 9, Binary 1001
- Decimal 10: Hexadecimal A, Binary 1010
- Decimal 11: Hexadecimal B, Binary 1011
- Decimal 12: Hexadecimal C, Binary 1100
- Decimal 13: Hexadecimal D, Binary 1101
- Decimal 14: Hexadecimal E, Binary 1110
- Decimal 15: Hexadecimal F, Binary 1111
The sum of two binary numbers 1101111 and 1100101 is ______.
Answer (Detailed Solution Below)
Digital Logic Question 10 Detailed Solution
Download Solution PDFThe sum of two binary numbers 1101111 and 1100101 is (11010100)2
Note: In Binary addition, 1 + 1 = 10 (0 is sum value and 1 is carry), 1 + 0 = 1, 0 + 1 = 1 and 0 + 0 = 0.
Calculation:
1 1 1 1 1 (Carry values)
1 1 0 1 1 1 1 (Binary number 1)
0 1 0 0 0 (Sum values)
+1 1 0 0 1 0 1 (Binary number 2)
-------------------
1 1 0 1 0 1 0 0 (Answer)
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The Octal equivalent of the binary number 1011101011 is:
Answer (Detailed Solution Below)
Digital Logic Question 11 Detailed Solution
Download Solution PDFAnswer: Option 2
Explanation:
An octal Equivalent of a binary number is obtained by grouping 3 bits from right to left.
001 | 011 | 101 | 011 |
1 | 3 | 5 | 3 |
So Octal Equivalent: 1353
Important Points
Binary to Octal code
000 |
001 |
010 |
011 |
100 |
101 |
110 |
111 |
0 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
The 8-bit 2's complement form of the number -14 is ______.
Answer (Detailed Solution Below)
Digital Logic Question 12 Detailed Solution
Download Solution PDFCalculation:
14 in binary form is represented as:
1410 = (00001110)2
Taking the 1's complement of the above, we get 11110001
Adding 1 to the 1's complement, we get the 2's complement representation of the number, i.e. 11110010
Since there is a 1 in the MSB, the number is a negative number with value -14.
∴ The 2's complement of -6410 contains 7 bits.
Boolean algebra obeys
Answer (Detailed Solution Below)
Digital Logic Question 13 Detailed Solution
Download Solution PDF
Name |
AND Form |
OR Form |
Identity law |
1.A = A |
0 + A = A |
Null Law |
0.A = 0 |
1 + A = 1 |
Idempotent Law |
A.A = A |
A + A = A |
Inverse Law |
AA’ = 0 |
A + A’ = 1 |
Commutative Law |
AB = BA |
A + B = B + A |
Associative Law |
(AB)C |
(A + B) + C = A + (B + C) |
Distributive Law |
A + BC = (A + B)(A + C) |
A(B + C) = AB + AC |
Absorption Law |
A(A + B) = A |
A + AB = A |
De Morgan’s Law |
(AB)’ = A’ + B’ |
(A + B)’ = A’B’ |
The number of 1s in the binary representation of (3 ⋆ 4096 + 15 ⋆ 256 + 5 ⋆ 16 + 3) are
Answer (Detailed Solution Below)
Digital Logic Question 14 Detailed Solution
Download Solution PDFApplication:
Decimal value = (3 ⋆ 4096 + 15 ⋆ 256 + 5 ⋆ 16 + 3)
It can be written as:
(2 + 1) × 212 + (8 + 4 + 2 + 20) × 28 + (4 + 1) × 24 + (2 + 1) × 20
21 × 212 + 20 × 212 + (23 + 22 + 21 + 20) × 28 + (22 + 20) × 24 + (21 + 20) × 20
This can be written as:
213 + 212 + 211 + 210 + 29 × 28 + 26 + 24 + 21 + 20
The binary representation will be:
(11111101010011)2
Which of the following pairs of octal and binary numbers are NOT equal?
Answer (Detailed Solution Below)
Digital Logic Question 15 Detailed Solution
Download Solution PDFThe correct answer is (11010)2 = (62)8
Key Points
Binary numbers and octal numbers are both used in computing. They are different ways of representing the same value - just like how "10" and "ten" are different ways of expressing the same quantity in decimal.
- Each digit of an octal number represents three binary digits because 23 = 8. Here's the mapping:
- "000" => "0"
- "001" => "1"
- "010" => "2"
- "011" => "3"
- "100" => "4"
- "101" => "5"
- "110" => "6"
- "111" => "7"
- Now let's convert the binary numbers to their equivalent octal numbers.
- (111 110 111)2 = (7 6 7)8
- (110 110 101)2 = (6 6 5)8
- (10 101 . 110)2 = (2 5 . 6)8
- (11 010)2 = (3 2)8 - Corrupted as the corresponding octal number should be (32)8 instead of (62)8.
Therefore, the 4th pair, (11010)2 = (62)8, is not equal.