Data Representation Flashcards
Q: What is the term for a single point in an image?
A: A pixel
Resolution is the number of what per inch?
pixels
What is the name for the method of compression where images are represented as groups of pixels (e.g. 3 red, 5 blue, 6 orange) rather than individual pixels (red,red,red,blue,blue,blue,blue,blue,orange,orange…)?
Lossless compression
Name an example of a file format that uses lossless compression
Png
Name an example of a file format that uses lossy compression
Jpg
What base is a hexadecimal number system?
16
How are alphanumeric symbols represented in binary?
They are transferred into a unique binary 7 digit number in the ASCII table where each symbol has a unique digit.
What does ASCII stand for?
American Standard Code for Information Interchange
How are colours represented?
Colours are usually shown in GUIs as a hexadecimal number 6 digits long representing the RGB ratio.
Why is analogue sound better than digital?
Analogue sound is represented as free flowing waves rather than being limited to the sample rate of digital, Digital sound is therefore a more limited version as the sound patterns’ frequency cannot exceed the sample rate of the speaker.
What is the Base system of binary?
Base 2
Which numbers are used in binary?
0 and 1
Binary is a base what system?
2
Which 2 numbers are used in Binary?
1 and 0
What is Binary?
A numerical system in which there are only 2 values for each digit 1 and 0.
Why can computers only operate using binary data?
Computers cannot easily read data from switches so they operate on whether a switch is in an on or off state and function differently depending on each.
What is 4 bits?
A nibble
What would happen if you added 2 8 bit numbers with a combined value of over 255?
The sum results in an overflow error causing the additional 256, which would require an additional bit to be stored, to be lost.
What base is hexadecimal?
16
How are we able to write the values 10 - 15?
As the letters A - F.
Why is it useful to use hexadecimal numbers?
When storing large binary digits as 4 binary numbers are able to be converted into a single hexadecimal digit i.e. 1011 = B. This makes it far easier for developers and designers to read long strings of binary data.
When is hexadecimal representation of data used?
When storing data on colours i.e. the common method is a 6 digit hexadecimal number representing the RGB values of a colour.
What base is a hexadecimal number system?
16
What base is a octal number system?
8
