Representing Data Flashcards
Text, Images and Sound
How is data transmitted inside a computer?
All data is transmitted as electrical signals that are either on or off
Why must data be converted into binary?
Computers can only process data in binary form (1s and 0s).
What happens when a key on the keyboard is pressed?
It is converted into a binary number so that the computer can process it.
What is ASCII?
A character encoding standard that assigns binary numbers to characters.
What is a limitation of ASCII?
It can only store 128 characters, which is insufficient for languages with large alphabets.
Why was Unicode developed?
To support multiple languages and characters beyond ASCII’s 128-character limit.
How do computers store images?
Images are made up of pixels, each represented by binary numbers.
How can black and white images be stored in binary?
Each pixel is either 1 (black) or 0 (white).
What is metadata in images?
Data about the image, such as its size (e.g., 10x10 pixels)
How does color representation work in binary?
Give an example of the basic colors represented by binary - white, blue, green and red
00 = White
01 = Blue
10 = Green
11 = Red
How does increasing bits per pixel affect colors?
State the colors per bits for the following bits - 1, 2, 3, 4, 8, and 16 bits
More bits allow more colors:
1 bit (0 or 1) = 2 colors
2 bits (00 to 11) = 4 colors
3 bits (000 to 111) = 8 colors
4 bits (0000 to 1111) = 16 colors
8 bits = 256 colors
16 bits = over 65000 colors
What is color depth?
The number of bits used to store each pixel’s color.
How does resolution affect image quality?
Higher resolution means more pixels, leading to better image quality but larger file sizes.
How do computers process sound?
Sound is captured by a microphone and converted into digital signal.
What does an Analog-to-Digital Converter (ADC) do in terms of sound?
It samples an analog sound wave at regular time intervals and converts it to binary.
What happens when sound is sampled?
The wave is approximate, losing some quality between sample points
How can sound quality be improved in digital format?
By increasing the sample rate (taking more samples per second).
What is sample rate?
The number of samples taken per second, measured in Hertz (Hz).
Why is compression used?
To reduce file size, saving storage space and improving transfer speed.
What are the two main types of compression?
Lossy and Lossless compression.
What is lossy compression?
A method that removes some data to reduce file size, leading to some quality loss.
Give examples of lossy compression formats.
JPEG (images)
MP3 (audio)
What is a disadvantage of lossy compression?
Lost data cannot be recovered.
What is lossless compression?
A compression method that reduces file size without losing data.
Give an example of lossless compression.
ZIP files.
What is the main drawback of lossless compression?
It does not reduce file sizes as much as lossy compression.
