1.4.1c Character sets: ASCII and Unicode Quiz: OCR Computer Science, Unit 4

The 20 questions

1. How many bits are used to represent a single character in standard ASCII?

   • 7 bits
   • 16 bits
   • 8 bits
   • 32 bits

2. How many unique characters can standard 7-bit ASCII represent in total?

   • 256
   • 64
   • 512
   • 128

3. What total number of unique characters can 8-bit Extended ASCII represent?

   • 128
   • 256
   • 512
   • 1024

4. Which decimal value represents the uppercase letter 'A' in the ASCII character set?

   • 32
   • 48
   • 97
   • 65

5. Which decimal value represents the lowercase letter 'a' in the ASCII character set?

   • 97
   • 32
   • 65
   • 48

6. What is the arithmetic difference between the ASCII values of lowercase and uppercase letters?

   • 32
   • 26
   • 64
   • 16

7. Which decimal value represents the numeric digit character '0' in standard ASCII?

   • 48
   • 64
   • 32
   • 0

8. Why was Unicode introduced as an alternative replacement for the ASCII character set?

   • Represent global languages
   • Compress text files
   • Encrypt raw text
   • Increase execution speed

9. How many bytes per character does the UTF-32 Unicode encoding format always use?

   • 1 byte
   • 8 bytes
   • 2 bytes
   • 4 bytes

10. Which main advantage does UTF-8 encoding offer over UTF-32 for English text files?

    • Faster processor speed
    • More available characters
    • Built-in file encryption
    • Smaller file size

11. What relationship exists between the first 128 characters of Unicode and standard ASCII?

    • Stored in reverse
    • They are identical
    • Bits are inverted
    • Shifted by 128

12. A text file contains 500 English characters encoded in UTF-8. How many bytes is this?

    • 500 bytes
    • 1000 bytes
    • 2000 bytes
    • 250 bytes

13. Which ASCII control character represents code 0 and indicates the end of a string?

    • NULL
    • Line feed
    • Carriage return
    • Escape

14. How many bits does variable-length UTF-8 encoding use for standard ASCII characters?

    • 8 bits
    • 32 bits
    • 24 bits
    • 16 bits

15. Which bit operation converts an ASCII uppercase letter to its equivalent lowercase letter?

    • Add 32
    • Add 16
    • Subtract 32
    • Subtract 16

16. Which feature can Unicode represent that standard ASCII is completely unable to support?

    • Decimal numbers
    • Emojis
    • Punctuation marks
    • Control characters

17. What is the maximum number of code points Unicode can theoretically address overall?

    • 256 characters
    • Over 1 million
    • 64 thousand
    • 65,536 characters

18. How many bytes are required to store a 10-character string using UTF-16 encoding?

    • 80 bytes
    • 40 bytes
    • 20 bytes
    • 10 bytes

19. What is a major disadvantage of using Unicode UTF-16 compared to standard ASCII?

    • No symbol support
    • Greater memory usage
    • Slower network cables
    • Fewer characters supported

20. What term describes the complete set of characters that a computer hardware and software can recognise?

    • Character map
    • Character set
    • Data structure
    • Encoding array

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