Octal and Hexadecimal Numbers MCQs
Octal and Hexadecimal Numbers – MCQs with Answers & Explanations
Class: CBSE Class 8 |
Subject: Computer Science |
Section: Number System |
Topic: Octal and Hexadecimal Numbers
Based on NCERT Syllabus | CBSE Board Examination Format
Based on NCERT Syllabus | CBSE Board Examination Format
1. The base of Octal Number System is:
Answer: b) 8
Explanation: Octal number system uses eight digits (0–7). Hence its base (radix) is 8.
Explanation: Octal number system uses eight digits (0–7). Hence its base (radix) is 8.
2. Which digit is not used in Octal system?
Answer: c) 8
Explanation: Octal digits range from 0 to 7. Digits 8 and 9 are not used.
Explanation: Octal digits range from 0 to 7. Digits 8 and 9 are not used.
3. The base of Hexadecimal system is:
Answer: d) 16
Explanation: Hexadecimal uses sixteen symbols: 0–9 and A–F.
Explanation: Hexadecimal uses sixteen symbols: 0–9 and A–F.
4. In Hexadecimal, A represents:
Answer: c) 10
Explanation: After 9, hexadecimal continues with A=10, B=11 … F=15.
Explanation: After 9, hexadecimal continues with A=10, B=11 … F=15.
5. Decimal equivalent of Octal 10 is:
Answer: a) 8
Explanation: (1×8¹)+0 = 8 in decimal.
Explanation: (1×8¹)+0 = 8 in decimal.
6. Decimal 15 in Hexadecimal is:
Answer: b) F
Explanation: In hexadecimal, F represents decimal 15.
Explanation: In hexadecimal, F represents decimal 15.
7. Largest digit in Octal system is:
Answer: b) 7
Explanation: Since base is 8, digits go from 0–7.
Explanation: Since base is 8, digits go from 0–7.
8. Largest digit in Hexadecimal system is:
Answer: b) F
Explanation: F represents 15, the highest single digit in hexadecimal.
Explanation: F represents 15, the highest single digit in hexadecimal.
9. Octal number 25 equals decimal:
Answer: b) 21
Explanation: (2×8)+5 = 16+5 = 21.
Explanation: (2×8)+5 = 16+5 = 21.
10. Hexadecimal 1A equals decimal:
Answer: c) 26
Explanation: 1×16 + 10 = 26.
Explanation: 1×16 + 10 = 26.
11. Which system uses digits 0–7?
Answer: b) Octal
Explanation: Octal system consists only of digits 0 to 7.
Explanation: Octal system consists only of digits 0 to 7.
12. Hexadecimal digit after 9 is:
Answer: a) A
Explanation: A represents decimal 10.
Explanation: A represents decimal 10.
13. Octal equivalent of decimal 9 is:
Answer: b) 11
Explanation: 9 ÷ 8 → quotient 1 remainder 1 → 11.
Explanation: 9 ÷ 8 → quotient 1 remainder 1 → 11.
14. Hexadecimal equivalent of decimal 12 is:
Answer: a) C
Explanation: C represents decimal 12.
Explanation: C represents decimal 12.
15. Which number system is commonly used in memory addressing?
Answer: b) Hexadecimal
Explanation: Hexadecimal is compact and easy to represent binary addresses.
Explanation: Hexadecimal is compact and easy to represent binary addresses.
16. Number of symbols in Hexadecimal system:
Answer: c) 16
Explanation: 0–9 plus A–F makes 16 symbols.
Explanation: 0–9 plus A–F makes 16 symbols.
17. Octal is derived from grouping of binary digits in:
Answer: b) Triplets
Explanation: Binary digits are grouped in 3s to convert into octal.
Explanation: Binary digits are grouped in 3s to convert into octal.
18. Hexadecimal is derived from grouping binary digits in:
Answer: c) 4
Explanation: Binary digits are grouped in 4s.
Explanation: Binary digits are grouped in 4s.
19. Decimal equivalent of Hexadecimal 10 is:
Answer: c) 16
Explanation: (1×16¹)+0 = 16.
Explanation: (1×16¹)+0 = 16.
20. Which system uses both numbers and alphabets?
Answer: d) Hexadecimal
Explanation: It uses digits 0–9 and letters A–F.
Explanation: It uses digits 0–9 and letters A–F.
