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Exam questions by topic

Edexcel curriculum (2015)


Algorithms

Application sof'wr

Ascii

Binary

Cache

Client-Server

Cloud

Compression

Computational think

CPU

Cyber security

Database

Fetch-d-e cycle

Embedded system

Encryption

Environment

Ethics

File size

Flow chart

Hexadecimal

High Level language

ISP/Internet

Law & Legislation

Logic

Magnetic HDD

Networking

Open source

Operating system

Optical storage

Peer to peer

Pictures (data rep)

Protocols

Run length encoding

RAM

ROM

Simulation software

Solid state HD

Sound

Stored program

Utility Sof'wre

Compression

Picture
Answer
​Any one of:
To reduce download time/increase transfer speed
To reduce amount of storage space required

Lossy compression

Picture
Answer
​Any two of:
Not all pixels are recorded
Quality/detail reduced
Only suitable when images have lots of the same pixels
Cannot reproduce original using the lossy data

Compression

Picture
Answer
​Any two of the following:

File sizes / download times will be reduced. (1)
Some loss of image data / image quality will occur. (1)
JPEGs allow image quality to be fine-tuned / the level of compression to be adjusted. (1)

Compression - lossless

Picture
Answer
​An explanation that makes reference to the following points:
• lossless compression ensures that no data is lost (1)
• so that the desktop published file can be restored so that it is exactly the same as the original (1)

Compression - lossy

Picture
Answer
​ Any two from:
• Data is removed during the compression process (1)
• The removed data is not normally noticed by a human (sight, sound) (1)
• The original contents of the file cannot be restored exactly (1)

Compression - RLE

Picture
Answer
​• Letters in correct order (1)
• Correct number (1)
Either: 3b 1r 4g 2r
Or
b3 r1 g4 r2

Run length encoding

Picture
Answer
​​Any one of:
R4B2R1Y3
R4B2RY3
4R2BR3Y
4R2B1R3Y
With one incorrect character or digit award a maximum of 1 mark.

Run length encoding

Picture
Answer
​This sequence has very few repeated patterns (1), therefore using a RLE will not lead to a significant reduction in the file size / not compress the image very much. (1)

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  • Edexcel GCSE CS
    • Past papers >
      • Paper 1 (New Spec)
      • Paper 1 (New Spec too)
      • Paper 2 (New Spec)
      • Sample assessment 1 (old spec)
      • Sample assessment 2 (old spec)
      • June 2015 (old spec)
    • Paper 1 (by topic) >
      • Algorithms
      • Application software
      • Ascii
      • Binary
      • Cache
      • Client Server
      • Cloud
      • Compression
      • Computational thinking
      • CPU
      • Cyber security
      • Fetch decode execute cycle
      • Embedded system
      • Encryption
      • File size
      • Flow chart
      • Hexadecimal
      • High Level language
      • ISP/Internet
      • Logic
      • Magnetic HDD
      • Networking
      • Open source
      • Operating system
      • Peer to peer
      • Images (Data representation)
      • Protocols
      • RAM
      • ROM
      • Run length encoding
      • Simulation software
      • Solid state HDD
      • Sound
      • Stored program concept
      • Utility software
    • Curriculum >
      • Binary
      • Hex
      • Data Representation
      • Compression
      • Encryption
      • What is a computer
      • How does a computer work
      • Hardware
      • Operating system
      • The CPU
      • Input devices
      • Data storage
      • Networks
      • Microcontrollers
      • Computational models
      • Emerging trends
      • Virtual machine
      • Models and simulators
      • Algorithms
    • Python >
      • Help with Python >
        • Finding python
        • Python coding >
          • Comments
          • Data types
          • Variables
          • If Else
          • If Elif Else
          • Functions
          • For loop
          • While loop
          • Data structures >
            • Looping thru 2D array
          • String slicing/indexing
          • user defined function
          • Local/global variable
          • Validation and try
          • methods
          • File I/O
          • Pseudocode
          • Modules
          • Classes
        • Python questions
  • Other exam boards
    • BTEC CS
    • OCR GCSE CS >
      • Past paper JUNE 2015
      • Past paper June 2014
      • Past paper MAY 2012
      • Past paper JAN 2011
      • Past paper JUN 2011
    • AQA AS-Level CS >
      • AS Curriculum >
        • Multiple choice questions
  • Contact/Upload/More
    • Contact us
    • upload
    • Scratch
    • Microbit ideas
  • Self test
    • 01 Random topics
    • 02 Programming
    • 03 Data
    • 04 Computers
    • 05 Communication and the internet
    • 06 The bigger picture
    • 07 Paper 2
✕