Data Representation

• What is the decimal number system also known as?

  Base 10
• What is the primary use of the binary number system?

  Used by computers to represent all data
• How many characters are in the hexadecimal number system?

  16 characters
• What are the characters used in the decimal number system?

  0-9
• What is the binary representation of the decimal number 20?

  10100
• What is the hexadecimal representation of the decimal number 26?

  1A
• What are the conversions between number bases mentioned?

  • Binary to Denary
  • Denary to Binary
  • Denary to Hexadecimal
  • Binary to Hexadecimal

  
• What is the most basic unit of data measurement?

  A bit
• How many bits are in a byte?

  8 bits
• What does 'B' represent in data measurement?

  A byte
• What does 'b' represent in data measurement?

  A bit
• How many bytes are in a kilobyte?

  1,024 bytes
• How many bits are in a kilobit?

  1,024 bits
• What is the size of a megabyte in kilobytes?

  1,024 kilobytes
• What is the size of a gigabyte in megabytes?

  1,024 megabytes
• What is the size of a terabyte in gigabytes?

  1,024 gigabytes
• What are the rules for binary addition?

  • 0 + 0 = 0
  • 1 + 0 = 1
  • 1 + 1 = 10 (binary for decimal 2)
  • 1 + 1 + 1 = 11 (binary for decimal 3)
• How does binary multiplication work?

  • Move digits to the left
  • Fill gaps with 0
  • Multiply by two: shift one place left
  • Multiply by four: shift two places left
• How does binary division work?

  • Move digits to the right
  • Fill gaps with 0
  • Divide by two: shift one place right
  • Divide by four: shift two places right
• What is a character set in computing?

  • A collection of characters a computer can use
  • Each character has a unique character code
  • Character codes are stored in binary
• What is the ASCII code for the character 'A'?

  65
• How many characters does ASCII support?

  128 characters
• What are the components of the ASCII table?

  • 32 control codes
  • 32 punctuation codes, symbols, and space
  • 26 upper case letters
  • 26 lower case letters
  • Numbers 0-9
• Why was Unicode developed?

  To accommodate more characters and symbols than ASCII
• How many characters does Unicode support?

  65,536 characters
• What is the concept of pixel in images?

  • Each square in a grid representing an image
  • Short for Picture Element
• What does colour depth refer to in images?

  The number of bits per pixel used to represent colors
• How is the size of an image measured?

  In pixels wide x pixels high
• How do you calculate the file size of an image?

  Height in pixels x Width in pixels x Colour depth per pixel
• What is the amplitude in sound?

  The height of the sound wave at the time it was sampled
• What is the sample rate in sound?

  The number of samples taken in one second
• How is sample rate measured?

  In Hertz (Hz)
• What does a higher sample rate indicate?

  A better quality sound file
• What is sample resolution?

  The number of bits used to store each sample
• How do you calculate the file size of a sound file?

  • Sample rate x Sample resolution x Duration
  • Larger files provide a more accurate representation
• What is the purpose of compression in data?

  • To reduce storage space required for data
  • To make files easier to transmit
  • Balancing file size reduction with quality
• What is lossy compression?

  A method where data is lost and cannot be recovered
• What is lossless compression?

  A method where no data is lost and original contents can be recovered
• What is Run Length Encoding (RLE)?

  • A lossless compression method
  • Relies on repeating digits
  • Stores runs of data in frequency/data pairs
• What is Huffman Coding?

  • A lossless compression method
  • Reduces bits needed to send/store messages
  • Uses a Huffman tree for unique character codes