Question Bank — Encoding Schemes and Number System

Section A — MCQs (10 questions, 1 mark each)

1. The base value of the octal number system is:
(a) 2 (b) 8 (c) 10 (d) 16

2. How many different characters can be encoded using 7-bit ASCII?
(a) 128 (b) 256 (c) 512 (d) 1024

3. UNICODE is a superset of ASCII because:
(a) It uses only 7 bits (b) Values 0–128 represent the same characters as ASCII (c) It supports only English (d) It is an 8-bit code

4. Which encoding scheme was developed in India in the mid-1980s to support Indian languages?
(a) ASCII (b) ISCII (c) UTF-8 (d) EBCDIC

5. In the hexadecimal number system, the decimal value 10 is represented by:
(a) 9 (b) A (c) F (d) 10

6. Assertion (A): Three binary digits are grouped together to obtain the equivalent octal digit.
Reason (R): The base of the octal number system is 8 and \(8 = 2^3\).
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

7. Assertion (A): Hexadecimal notation is preferred for representing 16-bit or 32-bit memory addresses.
Reason (R): A 16-bit binary address can be represented by only four hexadecimal digits, making it compact and easy to remember.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

8. The positional value of digit 5 in the decimal number 237.25 at position –2 is:
(a) \(10^{-1}\) (b) \(10^{-2}\) (c) \(8^{-2}\) (d) \(2^{-2}\)

9. Which of the following is not a positional number system?
(a) Binary (b) Octal (c) Hexadecimal (d) None of these

10. In UNICODE, the Devanagari character ‘अ’ is represented by the hexadecimal value:
(a) 0905 (b) 0041 (c) 0065 (d) 0900

Section B — Very Short Answer (6 questions, 2 marks each)

1. Define the term encoding as given in the chapter.

2. Differentiate between ASCII and ISCII on the basis of (i) number of bits used and (ii) languages supported.

3. What is the binary equivalent of the decimal number 65? Show the division steps briefly.

4. State the base values of binary, octal and hexadecimal number systems.

5. Convert the octal number (101)\(_8\) into its decimal equivalent using positional values.

6. Why are groups of 4 bits formed while converting a binary number to hexadecimal?

Section C — Short Answer (5 questions, 3 marks each)

1. Convert the decimal number (122)\(_{10}\) to its binary equivalent using the repeated division method. Show all steps.

2. The following conversion of (65)\(_{10}\) to octal contains an error. Identify the error and write the correct octal value with steps.
Given (incorrect): 8 | 65 → remainder 9, quotient 8 → (18)\(_8\)

3. Convert the binary number (10101100)\(_2\) to its equivalent octal number by grouping bits. Show the grouping.

4. Using positional values, convert the hexadecimal number (3A5)\(_{16}\) into its decimal equivalent.

5. Explain why UTF-32 occupies more storage space than UTF-8 for the same text, with reference to the chapter.

Section D — Long Answer (3 questions, 5 marks each)

1. Write the complete step-by-step algorithm (in numbered steps) to convert any positive decimal integer to its equivalent binary number using the repeated division method. Also show the dry-run (trace table) for the decimal number 122.

2. Explain with a diagram and steps how the decimal number 237.25 is evaluated using positional values in the decimal number system.

3. A 16-bit memory address is given as 1100000011110001. Convert it into (i) hexadecimal and (ii) octal form. Also state one advantage of using hexadecimal notation for memory addresses as mentioned in the chapter.

Section E — Case/Source-Based (2 questions, 4 marks each)

Case 1: A web designer wants to specify the colour RED on a webpage. The 24-bit binary code for RED is 11111111 00000000 00000000.
(a) Convert the given 24-bit binary code into its equivalent hexadecimal notation. (1)
(b) Write the hexadecimal colour code in the compact form used for web pages. (1)
(c) State the advantage of writing colour codes in hexadecimal instead of 24-bit binary. (1)
(d) If the same colour is to be represented in decimal (R,G,B) values, what will be the three decimal components? (1)

Case 2: A student types the Hindi word “अ” on a computer keyboard that supports Unicode.
(a) What is the hexadecimal Unicode value of the character “अ”? (1)
(b) Convert the hexadecimal value 0905 into its 16-bit binary equivalent. (1)
(c) Why can the same Unicode character be displayed correctly on any computer irrespective of the operating system? (1)
(d) Name the encoding scheme that was developed in India before Unicode to support Indian scripts and state how many additional characters it could represent beyond ASCII. (1)