Unicode Quiz - ICSE Class 11 Computer Science

Free practice quiz: Unicode (ICSE Class 11 Computer Science). 59 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

This ICSE Class 11 Computer Science practice quiz has 59 multiple-choice questions on Unicode, and 59 of them come with an explanation. Try the 5 sample questions below (tap an option to check yourself), then play the full quiz online. No sign-up needed.

Sample questions

1. What is the minimum number of bits required to represent the decimal integer -255 in two's complement, assuming a standard signed integer representation?

   1. 8
   2. 9
   3. 10
   4. 16
   Show answer

   Answer: B. 9

   To represent -255 in two's complement, we first consider the positive value 255. 255 in binary is 11111111 (8 bits). To find the two's complement of -255, we first find the one's complement of 255 (flipping all bits) and then add 1. However, this assumes we have enough bits for the positive number. Since 255 requires 8 bits, to represent a negative number, we need at least one more bit for the sign. Let's try with 9 bits. The range for 9-bit two's complement is -(2^(9-1)) to +(2^(9-1) - 1), which is -2^8 to 2^8 - 1, or -256 to 255. Since -255 falls within this range, 9 bits are sufficient. An 8-bit system can represent from -128 to +127, so it cannot represent -255. Therefore, the minimum number of bits required is 9.

2. In the ASCII encoding, the character 'a' has a decimal value of 97. What is the decimal value of the character 'z'?

   1. 121
   2. 122
   3. 123
   4. 124
   Show answer

   Answer: B. 122

   In ASCII, lowercase letters are assigned consecutive decimal values. Since 'a' is 97, 'b' is 98, 'c' is 99, and so on, we can determine the value of 'z' by counting. There are 26 letters in the English alphabet. 'z' is the 26th letter. So its value would be 97 + (26 - 1) = 97 + 25 = 122. Therefore, the decimal value of 'z' in ASCII is 122.

3. In the context of character encodings, what is the primary difference between ASCII and UTF-8?

   1. ASCII uses 8 bits per character, while UTF-8 uses a variable number of bytes (1 to 4).
   2. ASCII can represent more characters than UTF-8.
   3. UTF-8 is only used for English characters, while ASCII supports multiple languages.
   4. ASCII is a 7-bit encoding, while UTF-8 is always 8 bits.
   Show answer

   Answer: A. ASCII uses 8 bits per character, while UTF-8 uses a variable number of bytes (1 to 4).

   ASCII is a 7-bit encoding (often extended to 8 bits with an unused bit), limited to 128 (or 256) characters. UTF-8 is a variable-width encoding that uses 1 to 4 bytes to represent characters. Crucially, UTF-8 is backward compatible with ASCII: the first 128 characters (0-127) in UTF-8 are identical to the ASCII characters. UTF-8 supports the entire Unicode character set, encompassing far more characters than ASCII. While UTF-8's basic unit is a byte, its encoding can span multiple bytes for non-ASCII characters.

4. If ISCII is used to represent Indian languages, what is its typical bit depth per character?

   1. 7 bits
   2. 8 bits
   3. 16 bits
   4. Variable
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   Answer: B. 8 bits

   ISCII (Indian Standard Code for Information Interchange) is an 8-bit character encoding standard. This means it can represent up to 256 distinct characters. This was designed to accommodate the various Indian scripts and their characters.

5. What is the decimal value of the unsigned 16-bit binary number 1111111111111111?

   1. 65535
   2. 65536
   3. 32767
   4. 32768
   Show answer

   Answer: A. 65535

   For an unsigned N-bit integer, the maximum value is 2^N - 1. Here, N = 16. So the maximum value is 2^16 - 1. 2^16 is 65536. Therefore, 2^16 - 1 = 65535. The binary number 1111111111111111 consists of all ones, which represents the maximum value for a 16-bit unsigned integer.

More questions in this quiz

Answers and explanations are in the full quiz.

1. Which character encoding standard provides the widest range of characters, including support for emojis and ideograms from various languages?
2. Consider a system using 10 bits for representing signed integers in sign-magnitude representation. What is the largest positive integer that can be represented?
3. What is the decimal value of the unsigned 16-bit binary number 1111 0101 0010 1100?
4. In the context of Unicode, what does the term 'code point' refer to?
5. If the character 'A' is represented by the ASCII code 65, what is the hexadecimal representation of the character 'C'?
6. What is the primary advantage of using Unicode over older character encodings like ASCII for international text processing?
7. Consider the IEEE 754 double-precision floating-point representation. If a number has an exponent field of all ones and a significand field of all zeros, what does it represent?
8. Consider ISCII (Indian Standard Code for Information Interchange). If a character requires more than 8 bits for representation, how can it be handled within the ISCII framework, which is primarily 8-bit?
9. Which of the following best describes the purpose of the bias in floating-point number representation?
10. What is the value of the octal number 735 in decimal?
11. What is the primary advantage of UTF-8 over UTF-16 for representing text on the internet?
12. Consider a system representing signed integers using 8-bit two's complement. What is the decimal value of the binary number 11111110?
13. Which character encoding standard is the most widely used for web pages and general text files today, offering a balance of backward compatibility with ASCII and support for a vast range of global characters?
14. What is the decimal value of the unsigned 8-bit binary number 10101010?
15. What is the hexadecimal representation of the decimal number 255?
16. Consider the IEEE 754 single-precision representation. What is the decimal value of the bit pattern 0 00000000 00000000000000000000000?
17. Which character encoding system is designed to represent characters from all known scripts and symbols, including emojis?
18. In two's complement representation, what is the decimal value of the 5-bit binary number 11010?
19. What is the range of values representable by an unsigned 10-bit integer?
20. Which of the following is NOT a valid Unicode encoding scheme?
21. Consider the IEEE 754 single-precision format. The bit pattern 0 11111111 00000000000000000000000 represents:
22. What is the output of the logical XOR operation between the binary numbers 1011 and 0101?
23. Consider the ISO 8859-1 character encoding. What is its primary limitation compared to Unicode?
24. In the context of IEEE 754 single-precision floating-point numbers, what does the term 'denormalized' or 'subnormal' number refer to?
25. What is the decimal equivalent of the 7-bit ASCII character represented by the binary sequence 01000011?
26. Consider two's complement representation. Which of the following statements about the most negative number representable in N bits is true?
27. Which character encoding scheme is optimized for representing characters in many East Asian languages and uses a variable number of bytes, but often 2 bytes for common characters?
28. What is the range of integers representable by a 6-bit two's complement system?
29. What is the result of the logical AND operation between the binary numbers 1101 and 1010?
30. In the context of character encodings, what is the main advantage of UTF-8 over other Unicode encodings like UTF-16 for representing ASCII text?
31. What is the hexadecimal representation of the decimal number 511?
32. Consider the IEEE 754 single-precision representation. What does the bit pattern 0 11111111 10000000000000000000000 represent?
33. What is the decimal value of the 8-bit two's complement binary number 10000000?
34. Which of the following is a direct consequence of the fixed-width nature of ASCII encoding?
35. What is the ASCII hexadecimal representation for the DELETE control character?
36. Consider the IEEE 754 double-precision format. If the exponent field is all zeros and the significand field is non-zero, the number is considered:
37. What is the primary purpose of the ISCII standard?
38. What is the decimal value of the 8-bit two's complement binary number 01111111?
39. Which of the following Unicode encoding forms is most efficient in terms of storage space for typical English text?
40. What is the decimal value of the hexadecimal number 1A3?
41. In two's complement representation, what happens when you add 0110 and 0100 (both 4-bit numbers)?
42. Which character encoding standard is a 7-bit encoding primarily used for English characters and control codes?
43. Consider the IEEE 754 single-precision representation. What is the decimal value of the bit pattern 0 10000001 10000000000000000000000?
44. Which of the following is a consequence of using two's complement for representing signed integers regarding the distribution of numbers?
45. What is the primary characteristic that distinguishes Unicode from older character encodings like ASCII?
46. If a character is represented using 8-bit two's complement and its binary value is 11110001, what is its decimal value?
47. What is the decimal value of the hexadecimal number 3F8?
48. Consider the representation of floating-point numbers. What does the exponent field represent?
49. If a character is represented using 7-bit ASCII and its binary value is 01000001, what is its decimal value?
50. What is the primary advantage of using a fixed number of bits for representing signed integers in two's complement?
51. In Unicode, what is the purpose of surrogate pairs?
52. What is the decimal value of the hexadecimal number 2C5?
53. In the context of floating-point representation, what is the purpose of the 'significand' (or mantissa)?
54. What is the result of the logical OR operation between the binary numbers 1011 and 0101?

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