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OCR · GCSE · Computer Science

Free OCR GCSE Computer Science
Practice Paper

8 mixed-difficulty practice questions in the style of real OCR GCSE papers — answers, mark-scheme-style explanations, and the official exam structure all on one page.

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What the real OCR GCSE Computer Science paper looks like

Paper 1
Approximately 1 hour 30 minutes, ~70-100 marks. Covers Topics 1-4 of the specification.
Paper 2
Approximately 1 hour 30 minutes, ~70-100 marks. Covers Topics 5-8 of the specification.
Paper 3
Where applicable — e.g. Combined Science, Languages. Includes synoptic and applied questions.
Total exam time: ~3 hours across two or three papers.
Grading: Grades: 9 (highest) to 1 (lowest), with U (ungraded). A grade of 4 is a standard pass; 5 is a strong pass.

Mini practice paper: 6 questions

Mixed-difficulty questions from across the Computer Science syllabus. Tap "Show answer" after each to check yourself.

Q1 · Difficulty 1/3

Which type of translator converts high-level source code into machine code one line at a time, executing each line immediately?

  1. Interpreter
  2. Assembler
  3. Linker
  4. Compiler
Show answer & explanation
✓ Answer: A — Interpreter
An interpreter translates and executes high-level code line by line without producing a separate executable file. A compiler translates the entire program into machine code before execution. An assembler converts assembly language (low-level) into machine code. A linker combines object files but does not translate source code.
Q2 · Difficulty 2/3

Which of the following is a feature of an Integrated Development Environment (IDE) that helps a programmer identify errors before running the program?

  1. Syntax highlighting that visually marks code structure
  2. A compiler that converts object code to source code
  3. A version control system that tracks file changes
  4. A run-time error console that logs crashes
Show answer & explanation
✓ Answer: A — Syntax highlighting that visually marks code structure
Syntax highlighting uses colour and formatting to visually distinguish keywords, strings, and operators, helping programmers spot structural errors (such as unclosed strings) before running the program. A run-time error console only reports errors during execution. Version control tracks file history but does not identify code errors. Compilers translate source code to object code, not the reverse.
Q3 · Difficulty 2/3

A developer notices that her program produces incorrect results but does not crash or display any error messages. What type of error does this most likely indicate?

  1. A translation error produced by the assembler
  2. A logic error in the program's algorithm
  3. A run-time error caused by an illegal operation
  4. A syntax error flagged during compilation
Show answer & explanation
✓ Answer: B — A logic error in the program's algorithm
A logic error occurs when the program runs without crashing but produces wrong results because the algorithm is flawed — for example, using subtraction instead of addition. Syntax errors are caught by the translator before execution. Run-time errors cause the program to crash during execution. There is no category called a 'translation error' produced by an assembler.
Q4 · Difficulty 2/3

Which of the following best describes the purpose of syntax analysis during compilation?

  1. Converting source code characters into a stream of tokens
  2. Checking that the program's grammar rules are correctly followed
  3. Translating the intermediate code into machine code instructions
  4. Verifying that variable types are used consistently throughout the code
Show answer & explanation
✓ Answer: B — Checking that the program's grammar rules are correctly followed
Syntax analysis (parsing) checks that the sequence of tokens conforms to the grammar rules of the programming language, for example that every open bracket has a matching close bracket. Converting characters to tokens is lexical analysis. Checking variable types is semantic analysis. Producing machine code is code generation.
Q5 · Difficulty 3/3

A program written in a low-level language is ported to a new processor architecture. Which statement best explains why the program may not work on the new processor?

  1. High-level language translators are required to run low-level programs
  2. Low-level programs cannot be compiled into machine code
  3. Low-level languages are hardware-specific and tied to a particular processor's instruction set
  4. Low-level languages always use more memory than high-level languages
Show answer & explanation
✓ Answer: C — Low-level languages are hardware-specific and tied to a particular processor's instruction set
Low-level languages, including assembly language, are written for a specific processor's instruction set architecture. Instructions valid on one CPU may not exist or may have different binary encodings on another. High-level languages abstract away hardware differences and can be recompiled for different architectures. The remaining options are factually incorrect.
Q6 · Difficulty 2/3

A student writes a Python program on her school computer. She wants to run the same program at home without installing Python. Which translator should she have used instead?

  1. An assembler, because it converts code to binary directly
  2. A linker, because it combines all required files together
  3. A compiler, because it produces a standalone executable
  4. An interpreter, because it runs code on any machine
Show answer & explanation
✓ Answer: C — A compiler, because it produces a standalone executable
A compiler produces a standalone executable file that can be run without the original translator being installed on the target machine. An interpreter requires the interpreter software to be present every time the program runs. An assembler only works with assembly language, not Python. A linker combines object files but does not translate high-level source code.
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OCR GCSE Computer Science FAQ

What does the OCR GCSE Computer Science exam look like?
The OCR GCSE Computer Science exam is structured across 3 components. Paper 1: Approximately 1 hour 30 minutes, ~70-100 marks. Covers Topics 1-4 of the specification. Paper 2: Approximately 1 hour 30 minutes, ~70-100 marks. Covers Topics 5-8 of the specification. Paper 3: Where applicable — e.g. Combined Science, Languages. Includes synoptic and applied questions. Total exam time: ~3 hours across two or three papers.
Can I download a free OCR GCSE Computer Science past paper?
Real OCR past papers are published directly by OCR on their official website. Kramizo doesn't redistribute copyrighted past papers, but we do generate free AI-written practice papers in the exact same style — same command words, same difficulty tier, same mark conventions. Use this practice paper as warm-up, then time yourself on official past papers before exam day.
How is OCR GCSE Computer Science graded?
Grades: 9 (highest) to 1 (lowest), with U (ungraded). A grade of 4 is a standard pass; 5 is a strong pass. Kramizo's practice questions are tagged with difficulty 1-3 mapping roughly to the lower, middle, and top grade boundaries you'll encounter in the real exam.