2.4 G3 Computhink - Data Representation (Text)

Refer to the ASCII table. What is the 8-bit ASCII code for the uppercase letter ‘H’?

• 01001000₂
• 01101000₂
• 00101000₂
• 01000001₂

Refer to ASCII table. What is the hexadecimal representation of the ASCII code for the exclamation mark ‘!’?

• 21₁₆
• 2A₁₆
• 3F₁₆
• 41₁₆

Refer to ASCII table. Decode the following sequence of bytes using an ASCII table. Each byte represents a character and is encoded as 2 hexadecimal digits: 48 45 4C 4C 4F

• Hello
• HELLO
• hello
• WORLD
• world

Answer explanation

H - > 48, E ->45, L -> 4C, O -> 4F

How many characters can be represented in 8-bit Extended ASCII?

• 64
• 128
• 256
• 512

Answer explanation

Extended ASCII uses 8 bits per character, allowing for 2⁸ = 256 characters. The original 7-bit ASCII could only store 128 characters.

How many characters can be represented in 7-bit ASCII?

• 64
• 128
• 256
• 512

Answer explanation

Extended ASCII uses 8 bits per character, allowing for 2⁸ = 256 characters. The original 7-bit ASCII could only store 128 characters.

Which of the following best describes the main difference between ASCII and Unicode?

• Unicode is only used for English characters.
• Unicode uses variable-length encoding while ASCII uses a fixed-length 8-bit encoding.
• ASCII can store more characters than Unicode.
• Unicode and ASCII are exactly the same

Answer explanation

ASCII is fixed at 8 bits per character (Extended ASCII). Unicode allows variable-length encoding (8 to 32 bits), making it more suitable for multiple languages.

Which of the following correctly explains how ASCII characters are stored in a computer?

• Each character is stored as an individual pixel in memory.
• Each character is assigned a unique binary number and stored as 8 bits (1 byte).
• Characters are stored directly as text without conversion into binary.
• Characters are stored as a sequence of numbers, but only using hexadecimal encoding.

Refer to the ASCII table. Which of the following statements about the first 32 ASCII codes (0 to 31) is true? (Select all that apply)

• They represent non-printing control characters, such as Backspace and Escape (Esc).
• They are used to perform special functions on devices like teleprinters.
• They are commonly used to store visible text characters like letters and numbers.
• ASCII code 12 represents the Delete (DEL) key on the keyboard.

Answer explanation

ASCII codes 0 to 31 include non-printing control characters like Backspace (8) and Escape (27). The control characters were originally used in teleprinters and are still used in computing today. The last ASCII code 127 is also used to represent the special input of typing the Delete key on the keyboard. Printable characters (letters, numbers, symbols) start from ASCII code 32 and above.