Computer Science - Representing data 3.5 / 5 based on 3 ratings ? ComputingRepresenting dataGCSEOCR Created by: becky.65Created on: 20-05-15 11:59 How are all the symbols on a computer displayed? By a code 1 of 33 What are the codes stored in? Binary 2 of 33 What is the character set for the computer? The list of codes and matching characters 3 of 33 How many bits does ASCII use? 7 bits or extended ASCII uses 8 bits 4 of 33 How many bits does Unicode use? 16 or 32 bits 5 of 33 What does Unicode provide A character set for a computer that includes a wide range of specialist symbols 6 of 33 Since Unicode keeps the same assignment of codes for the original ASCII codes so what could ASCII be considered as now? A subset of Unicode 7 of 33 How are images stored on a computer In binary 8 of 33 How is the computer able to work out how to turn binary values into the image? The file with the binary data contains metadata 9 of 33 What is a pixel? One 'dot' in the image 10 of 33 What does the number of bits we use for a pixel determine? How many colours each dot can represent 11 of 33 What two things need to get greater for more bits needed to store the data The more bits per pixel and the greater the colour depth 12 of 33 What is 16bpp called? High colour 13 of 33 What is 24bpp called? True colour 14 of 33 What is the resolution? The number of pixels per unit 15 of 33 What is a bitmapped image? An image built up from pixels 16 of 33 What happens when a bitmapped image is displayed enlarged on a screen? The actual image size does not change, the dots just get bigger and the image becomes pixelated 17 of 33 Why are sound files described by metadata? To make sure the computer can interpret the data accurately 18 of 33 What does the data stored include? The audio codec and the sample rate 19 of 33 What form is sound in? Analogue form 20 of 33 Since it is in analogue form, what needs to happen for sound to be transferred to a computer? It needs to be digitally sampled 21 of 33 What is the sample interval? Often used to describe the sample rate and is the time between samples being taken 22 of 33 So the higher the sample interval the...? Lower the sample rate 23 of 33 What happens when sound is sampled at a low rate? Very few samples are taken, there is a poor match between the original sound and the sampled sound and a small file size is required 24 of 33 What happens when sound is sampled at a higher rate? Many more samples are taken, there is a good match between the original sound and the sampled sound and a large file size is required 25 of 33 What is the bit rate? The amount of space to to store each second of the sample 26 of 33 What does a higher bit rate mean? More accurate sampling at each point which gives better quality and more data needs to be stored which needs a larger file size 27 of 33 What does the CPU when it fetches an instruction? It decodes it in order to find out what to do next 28 of 33 What are the two parts of the instruction Operator, which is the instruction part ad the operand which is the data part 29 of 33 What does the operator binary code represent? An operation, for example ADD 30 of 33 What does the operand represent? The data that the operator uses 31 of 33 What is the accumulator? A special register in the CPU used to store the results of any calculation 32 of 33 How does a computer tell the difference between data and instructions? It cannot tell the difference between them and simply deals with what it finds according to what us expects to find 33 of 33
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