AQA A-Level Computer Science Paper 1 Sample 2023
This sample paper tests the theory-heavy concepts you'll face in the real A-Level Computer Science exam — the kind of questions that catch students out because they require precision and deep understanding rather than just memorisation. You'll encounter multiple-choice questions on data representation, algorithm complexity, and the architecture of real computer systems, alongside short-answer items that demand you explain *why* a system works, not just what it does. This is Paper 1 material for AQA A-Level Computer Science (Year 12 / Lower Sixth), drawn from the fundamentals of programming, data structures, algorithms, and theory of computation that underpin the entire course. By the end, you'll have practised the exact style and timing of the real exam, and you'll spot the common misconceptions examiners use to separate 7s from 8s.
Questions in this quiz
Answers hidden — play to find out.
- Question 1
When a 32-bit signed integer using two's complement representation overflows, the result wraps around. What value does the decimal number +2147483647 become when 1 is added to it?
- Question 2
A Unicode character requires 3 bytes (24 bits) to encode in UTF-8. How many different characters can be uniquely represented using this 24-bit code?
- Question 3
What is the result of converting the binary number 11010110 to hexadecimal?
- Question 4
True or False: A floating-point number represented using 32 bits (single precision) can exactly represent the decimal value 0.1.
- Question 5
An algorithm has a time complexity of . If the algorithm takes 100 milliseconds to process 1000 items, approximately how long will it take to process 10000 items?
- Question 6
Which of the following sorting algorithms has a worst-case time complexity of ?
- Question 7
A stack data structure follows which principle?
- Question 8
What is the name of the CPU register that stores the memory address of the next instruction to be executed?
- Question 9
True or False: The Von Neumann architecture requires a separate memory location for each instruction and each data value, so programs cannot modify their own code at runtime.
- Question 10
In the fetch–decode–execute cycle, what is the purpose of the Memory Address Register (MAR)?
- Question 11
Which of the following operations cannot be implemented using only NAND gates?
- Question 12
A Turing machine can be thought of as having an infinitely long tape divided into cells, a read/write head, and a finite state automaton. Which statement best describes the relationship between a Turing machine and a real computer?
- Question 13
What is the term for an algorithm that produces a guaranteed optimal solution for a problem in polynomial time?
- Question 14
In a linked list, each node contains a data field and a pointer to the next node. Compared to an array, what is the main disadvantage of a linked list?