Section 2 - Computer Science - Data Representation

What are the smallest measure of data?

Bits

What is a binary number?

A number made up of 0s and 1s used by computers to represent all data.

How do you convert binary to decimal?

Multiply each bit by 2n starting from the right and add the results.

What is a hexidecimal and why is it used in computing?

It is a base-16 number, it includes numbers 0-9 and letters A-F. It is easier for humans to read than binary.

How many bits are in one hexidecimal?

4 bits

How are characters stored in binary?

Using character sets like ASCII or Unicode which assign a binary value to each number

What affects image file size and what do they affect?

Resolution - number of pixels

Colour depth - bits per pixel

How are images represented?

As a grid of pixels each with a binary colour value

How is sound stored digitally?

By sampling the sound wave at regular intervals

Whats the largest measure of data?

Petabyte (1000 terabytes)

What affects the sound file size?

Sample rate

bit depth

channels

What is data compression?

Reducing file size for storage or transmission

Name two types of compression

Lossy - permananetly removes data

Lossless - keeps all data