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Daily Practice · GCSE Computer Science

January 2015 - GCSE Computer Science 5-a-day

Every GCSE Computer Science sheet published in January 2015, with answers. Systems, data representation, networks, algorithms and programming.

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January 2015

31 sheets · 155 questions · GCSE

January 2015 compilationAll answers

Every sheet in January 2015

The same date always regenerates the same five questions, so a sheet you print today is the sheet a classmate prints tomorrow.

  1. 1st January 2015A simple cipher shifts every letter 2 places forward in the alphabet, wrapping around so Y becomes A and Z becomes B. Encrypt the plaintext CAT using this cipher.
  2. 2nd January 2015A 2D array grid is declared as grid[4][6]. State how many rows and columns it has and how many elements it holds in total.
  3. 3rd January 2015A mono sound clip has a sample rate of 4000 Hz and lasts 2 seconds. Calculate the total number of samples taken.
  4. 4th January 2015State the type of program that is typically stored in ROM.
  5. 5th January 2015State one reason a small business might choose to use open source software instead of proprietary (closed source) software.
  6. 6th January 2015A FOR loop runs: total = 0, FOR i = 1 TO 4, total = total + i, NEXT i. State the value of total after the loop finishes.
  7. 7th January 2015State the pseudocode operator commonly used to join (concatenate) two strings, then show how it joins 'Rev' and 'ision' to produce 'Revision'.
  8. 8th January 2015State the typical maximum capacity of a single-layer DVD.
  9. 9th January 2015State the layer that IP operates in, and describe its job.
  10. 10th January 2015State what is meant by a syntax error.
  11. 11th January 2015Define the term 'primary key' as used in a database table.
  12. 12th January 2015What type of utility software reorganises files on a hard disk so fragmented parts are stored closer together?
  13. 13th January 2015Calculate the maximum number of comparisons required by a binary search on a sorted list of 512 items.
  14. 14th January 2015Given P = 0 and Q = 1, state the value of P OR Q.
  15. 15th January 2015Convert the 8-bit binary number 10110100 directly to hexadecimal by splitting it into nibbles.
  16. 16th January 2015A network administrator is connecting 10 computers in a server room. Calculate the number of cables needed for a full mesh topology, and state the number needed for a star topology with one central switch.
  17. 17th January 2015Describe what syntax highlighting is and how it helps a programmer.
  18. 18th January 2015Convert the 4-bit binary number 1101 to denary.
  19. 19th January 2015Two CPUs are compared for a task optimised for multiple cores: CPU A has 2 cores at 4.2 GHz; CPU B has 6 cores at 3.0 GHz. Explain which CPU is likely to perform better for this task.
  20. 20th January 2015State why an organisation might employ penetration testers to test its network.
  21. 21st January 2015Trace this algorithm with data = [4, 9, 2, 9, 7] and state the final output. total = 0; count = 0; for i = 0 to 4: if data[i] > 5 then total = total + data[i] and count = count + 1; next i; print(total, count).
  22. 22nd January 2015State one example of a file format that commonly uses lossy compression.
  23. 23rd January 2015State how many bits are in one byte, and how many bytes are in one kibibyte (KiB).
  24. 24th January 2015State whether the source code of proprietary (closed source) software is normally available for the public to view.
  25. 25th January 2015Write one line of pseudocode that converts the string stored in heightInput into a real number and stores it in a variable called height.
  26. 26th January 2015A function is defined as: FUNCTION addTax(price) RETURN price x 1.2 ENDFUNCTION. Another line of code runs: total <- addTax(20) + addTax(30). Trace both function calls and state the final value of total.
  27. 27th January 2015Order these units of data from smallest to largest: megabyte, byte, gigabyte, kilobyte.
  28. 28th January 2015Explain the role of TCP when a large file is downloaded.
  29. 29th January 2015Give one example of erroneous test data for a field that only accepts whole numbers from 1 to 10.
  30. 30th January 2015A table called staff has fields staffId, name, department and salary, storing these records: staffId | name | department | salary, 1 | Ben | Sales | 24000, 2 | Chloe | IT | 31000, 3 | Dan | Sales | 27000. State which staffId(s) would be returned by: SELECT staffId FROM staff WHERE department = 'Sales' AND salary > 25000;
  31. 31st January 2015Each pair from the previous question is stored using 2 bytes. Calculate the compression ratio achieved, given the uncompressed row (1 byte per pixel) uses 8 bytes.