GCSE Computer Science 2025”2026 REVIEW EXAM 150 QUESTIONS
AND CORRECTION QUESTIONS WITH RATIONALES COVERING THE
RECENT TESTED QUESTIONS GUARANTEE A+ GRADE
1. Which of the following best describes an algorithm?
A. A programming language
B. A data type
C. ☑ A set of step-by-step instructions to solve a problem
D. A variable name
Rationale: An algorithm is a precise sequence of steps that describes how to solve a specific
problem logically.
2. What is the main purpose of an IDE (Integrated Development Environment)?
A. To execute compiled machine code
B. ☑ To provide tools for writing, testing, and debugging programs
C. To store binary data only
D. To display websites
Rationale: An IDE offers a text editor, debugger, and compiler/interpreter to help developers
create and manage code efficiently.
3. What does CPU stand for?
A. Central Processing Utility
B. Computer Processing Unit
C. ☑ Central Processing Unit
D. Core Programming Unit
Rationale: The CPU is the main processor that performs calculations and controls all operations
within a computer.
4. Which component temporarily stores data being processed by the CPU?
A. Hard drive
B. ☑ RAM (Random Access Memory)
C. Cache
D. ROM
Rationale: RAM holds data and instructions currently in use; it’s volatile and cleared when the
system is turned off.
,5. What is binary used for in computers?
A. To represent colors
B. ☑ To represent data using 0s and 1s
C. To calculate hexadecimal values
D. To measure clock speed
Rationale: Computers use binary (base-2) because their circuits can represent two states: on (1)
and off (0).
6. What is meant by "data compression"?
A. Enlarging file size
B. ☑ Reducing file size for faster transmission or storage
C. Encrypting data
D. Converting data to binary
Rationale: Compression minimizes storage space and speeds up data transfer while maintaining
acceptable quality.
7. Which of these is an example of secondary storage?
A. CPU cache
B. RAM
C. ☑ Hard disk drive (HDD)
D. ALU
Rationale: Secondary storage (like HDDs and SSDs) retains data permanently, unlike volatile
memory.
8. What does the term “iteration” mean in programming?
A. Making a variable constant
B. ☑ Repeating a section of code using loops
C. Defining a new function
D. Testing a program once
Rationale: Iteration means executing a set of instructions multiple times using loops like for or
while.
9. Which logic gate outputs TRUE only when both inputs are TRUE?
A. OR
B. ☑ AND
C. NOT
,D. XOR
Rationale: The AND gate outputs 1 only if both inputs are 1; otherwise, it outputs 0.
10. What is the purpose of the operating system (OS)?
A. To connect the computer to the internet
B. ☑ To manage hardware, software, and system resources
C. To compile source code
D. To encrypt user data
Rationale: The OS coordinates hardware and software operations, handling memory, files, and
input/output devices.
11. What does the term “debugging” mean?
A. Encrypting software
B. ☑ Identifying and fixing errors in code
C. Writing pseudocode
D. Testing hardware
Rationale: Debugging involves locating and resolving coding errors that prevent a program from
running correctly.
12. Which of these represents an example of a high-level language?
A. Machine code
B. Assembly
C. ☑ Python
D. Binary
Rationale: High-level languages like Python or Java are easier for humans to read and write
than machine or assembly code.
13. Which number system uses digits 0–9 and letters A–F?
A. Binary
B. Decimal
C. ☑ Hexadecimal
D. Octal
Rationale: Hexadecimal (base-16) uses 0–9 and A–F to represent values compactly in
computing.
, 14. What is an array?
A. A single data item
B. ☑ A data structure storing multiple items of the same type
C. A Boolean operator
D. A subroutine
Rationale: Arrays store several related data items under one name, accessible by index
numbers.
15. What does ‘LAN’ stand for?
A. Large Area Network
B. ☑ Local Area Network
C. Logical Access Node
D. Linked Array Network
Rationale: A LAN connects devices in a limited area (e.g., a school or office), allowing fast
communication.
16. What is encryption used for?
A. Compressing data
B. ☑ Securing data by converting it into unreadable form
C. Storing passwords
D. Formatting drives
Rationale: Encryption converts plaintext into ciphertext, protecting sensitive information from
unauthorized access.
17. What is the main function of the ALU (Arithmetic Logic Unit)?
A. Storing data
B. ☑ Performing mathematical and logical operations
C. Managing memory
D. Controlling hardware devices
Rationale: The ALU executes arithmetic (e.g., addition) and logical (e.g., comparisons)
operations within the CPU.
18. What is meant by “machine code”?
A. Code written in English
B. ☑ Instructions executed directly by the CPU
C. A compiled high-level program
AND CORRECTION QUESTIONS WITH RATIONALES COVERING THE
RECENT TESTED QUESTIONS GUARANTEE A+ GRADE
1. Which of the following best describes an algorithm?
A. A programming language
B. A data type
C. ☑ A set of step-by-step instructions to solve a problem
D. A variable name
Rationale: An algorithm is a precise sequence of steps that describes how to solve a specific
problem logically.
2. What is the main purpose of an IDE (Integrated Development Environment)?
A. To execute compiled machine code
B. ☑ To provide tools for writing, testing, and debugging programs
C. To store binary data only
D. To display websites
Rationale: An IDE offers a text editor, debugger, and compiler/interpreter to help developers
create and manage code efficiently.
3. What does CPU stand for?
A. Central Processing Utility
B. Computer Processing Unit
C. ☑ Central Processing Unit
D. Core Programming Unit
Rationale: The CPU is the main processor that performs calculations and controls all operations
within a computer.
4. Which component temporarily stores data being processed by the CPU?
A. Hard drive
B. ☑ RAM (Random Access Memory)
C. Cache
D. ROM
Rationale: RAM holds data and instructions currently in use; it’s volatile and cleared when the
system is turned off.
,5. What is binary used for in computers?
A. To represent colors
B. ☑ To represent data using 0s and 1s
C. To calculate hexadecimal values
D. To measure clock speed
Rationale: Computers use binary (base-2) because their circuits can represent two states: on (1)
and off (0).
6. What is meant by "data compression"?
A. Enlarging file size
B. ☑ Reducing file size for faster transmission or storage
C. Encrypting data
D. Converting data to binary
Rationale: Compression minimizes storage space and speeds up data transfer while maintaining
acceptable quality.
7. Which of these is an example of secondary storage?
A. CPU cache
B. RAM
C. ☑ Hard disk drive (HDD)
D. ALU
Rationale: Secondary storage (like HDDs and SSDs) retains data permanently, unlike volatile
memory.
8. What does the term “iteration” mean in programming?
A. Making a variable constant
B. ☑ Repeating a section of code using loops
C. Defining a new function
D. Testing a program once
Rationale: Iteration means executing a set of instructions multiple times using loops like for or
while.
9. Which logic gate outputs TRUE only when both inputs are TRUE?
A. OR
B. ☑ AND
C. NOT
,D. XOR
Rationale: The AND gate outputs 1 only if both inputs are 1; otherwise, it outputs 0.
10. What is the purpose of the operating system (OS)?
A. To connect the computer to the internet
B. ☑ To manage hardware, software, and system resources
C. To compile source code
D. To encrypt user data
Rationale: The OS coordinates hardware and software operations, handling memory, files, and
input/output devices.
11. What does the term “debugging” mean?
A. Encrypting software
B. ☑ Identifying and fixing errors in code
C. Writing pseudocode
D. Testing hardware
Rationale: Debugging involves locating and resolving coding errors that prevent a program from
running correctly.
12. Which of these represents an example of a high-level language?
A. Machine code
B. Assembly
C. ☑ Python
D. Binary
Rationale: High-level languages like Python or Java are easier for humans to read and write
than machine or assembly code.
13. Which number system uses digits 0–9 and letters A–F?
A. Binary
B. Decimal
C. ☑ Hexadecimal
D. Octal
Rationale: Hexadecimal (base-16) uses 0–9 and A–F to represent values compactly in
computing.
, 14. What is an array?
A. A single data item
B. ☑ A data structure storing multiple items of the same type
C. A Boolean operator
D. A subroutine
Rationale: Arrays store several related data items under one name, accessible by index
numbers.
15. What does ‘LAN’ stand for?
A. Large Area Network
B. ☑ Local Area Network
C. Logical Access Node
D. Linked Array Network
Rationale: A LAN connects devices in a limited area (e.g., a school or office), allowing fast
communication.
16. What is encryption used for?
A. Compressing data
B. ☑ Securing data by converting it into unreadable form
C. Storing passwords
D. Formatting drives
Rationale: Encryption converts plaintext into ciphertext, protecting sensitive information from
unauthorized access.
17. What is the main function of the ALU (Arithmetic Logic Unit)?
A. Storing data
B. ☑ Performing mathematical and logical operations
C. Managing memory
D. Controlling hardware devices
Rationale: The ALU executes arithmetic (e.g., addition) and logical (e.g., comparisons)
operations within the CPU.
18. What is meant by “machine code”?
A. Code written in English
B. ☑ Instructions executed directly by the CPU
C. A compiled high-level program
