250+ TOP MCQs on Number System – 1 and Answers

Digital Electronics/Circuits Multiple Choice Questions on “Number System – 1”.

1. Any signed negative binary number is recognised by its ________
A. MSB
B. LSB
C. Byte
D. Nibble
Answer: A
Clarification: Any negative number is recognized by its MSB (Most Significant Bit).
If it’s 1, then ít’s negative, else if it’s 0, then positive.

2. The parameter through which 16 distinct values can be represented is known as ________
A. Bit
B. Byte
C. Word
D. Nibble
Answer: C
Clarification: It can be represented up to 16 different values with the help of a Word. Nibble is a combination of four bits and Byte is a combination of 8 bits. It is “word” that is said to be a collection of 16-bits on most of the systems.

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
Answer: B
Clarification: On multiplying the decimal number continuously by 2, the binary equivalent is obtained by the collection of the integer part. However, if it’s an integer, then it’s binary equivalent is determined by dividing the number by 2 and collecting the remainders.

4. The representation of octal number (532.2)8 in decimal is ________
A. (346.25)10
B. (532.864)10
C. (340.67)10
D. (531.668)10
Answer: A
Clarification: Octal to Decimal conversion is obtained by multiplying 8 to the power of base index along with the value at that index position.
(532.2)8 = 5 * 8² + 3 * 8¹ + 2 * 8⁰ + 2 * 8^-1 = (346.25)10

5. The decimal equivalent of the binary number (1011.011)2 is ________
A. (11.375)10
B. (10.123)10
C. (11.175)10
D. (9.23)10
Answer: A
Clarification: Binary to Decimal conversion is obtained by multiplying 2 to the power of base index along with the value at that index position.
1 * 2³ + 0 * 2² + 1 * 2¹ +1*2⁰ + 0 * 2^-1 +1 * 2^-2 + 1 * 2^-3 = (11.375)10
Hence, (1011.011)2 = (11.375)10

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. It requires small string of 1’s and large string of 0’s to represent a decimal number
Answer: A
Clarification: The most vital drawback of binary system is that it requires very large string of 1’s and 0’s to represent a decimal number. Hence, Hexadecimal systems are used by processors for calculation purposes as it compresses the long binary strings into small parts.

7. The decimal equivalent of the octal number (645)₈ is ______
A. (450)₁₀
B. (451)₁₀
C. (421)₁₀
D. (501)₁₀
Answer: C
Clarification: Octal to Decimal conversion is obtained by multiplying 8 to the power of base index along with the value at that index position.
The decimal equivalent of the octal number (645)₈ is 6 * 8² + 4 * 8¹ + 5 * 8⁰ = 6 * 64 + 4 * 8 + 5 = 384 + 32 + 5 = (421)₁₀.

8. The largest two digit hexadecimal number is ________
A. (FE)16
B. (FD.16
C. (FF)16
D. (EF)16
Answer: C
Clarification: (FE)16 is 254 in decimal system, while (FD.16 is 253. (EF)16 is 239 in decimal system. And, (FF)16 is 255. Thus, The largest two-digit hexadecimal number is (FF)16.

9. Representation of hexadecimal number (6DE)H in decimal:
A. 6 * 16² + 13 * 16¹ + 14 * 16⁰
B. 6 * 16² + 12 * 16¹ + 13 * 16⁰
C. 6 * 16² + 11 * 16¹ + 14 * 16⁰
D. 6 * 16² + 14 * 16¹ + 15 * 16⁰
Answer: A
Clarification: Hexadecimal to Decimal conversion is obtained by multiplying 16 to the power of base index along with the value at that index position.
In hexadecimal number D & E represents 13 & 14 respectively.
So, 6DE = 6 * 16² + 13 * 16¹ + 14 * 16⁰.

10. The quantity of double word is ________
A. 16 bits
B. 32 bits
C. 4 bits
D. 8 bits
Answer: B
Clarification: One word means 16 bits, Thus, the quantity of double word is 32 bits.