Lesson T1.2.3

T1.2.3 Comparing the utility of algorithms Quiz: KS3 Computing, Unit 1

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

In partnership with Revision Ninja

Lesson T1.2.3, Comparing the utility of algorithms: 20 multiple choice questions for the KS3 Computing (National Curriculum), Unit 1: Computational thinking and algorithms, written with Revision Ninja.

Host it live on the board and students join with a game code on their own devices, or revise alone with Free Play. The answers are revealed in the game.

Host this setFree Play

The 20 questions

  1. Why compare two different algorithms that solve the same problem?

    • Change the syntax
    • Judge efficiency
    • Reduce file size
    • Increase complexity

  2. Which measure is commonly used to judge an algorithm's performance?

    • Font style
    • Variable names
    • Number of steps
    • Line count

  3. Between binary and linear search on 1000 sorted items, which needs fewer checks worst-case?

    • Both are equal
    • Linear search
    • Neither works
    • Binary search

  4. Which sorting algorithm makes at most one swap per pass?

    • Selection sort
    • Merge sort
    • Insertion sort
    • Bubble sort

  5. Algorithm A takes 5 seconds and Algorithm B takes 2 seconds. Which is more efficient?

    • Cannot be told
    • Algorithm A
    • Both are equal
    • Algorithm B

  6. When two algorithms are both correct, which factors determine the better choice?

    • Author and date
    • Font and colour
    • Speed and memory
    • File name length

  7. Which factor is irrelevant when comparing the utility of two algorithms?

    • Screen display colour
    • Memory usage
    • Execution time
    • Number of steps

  8. Linear search on 50 items takes about 25 checks on average. About how many checks does binary search need on 50 sorted items?

    • About 6
    • About 25
    • About 1
    • About 50

  9. What does worst-case behaviour provide when comparing algorithms?

    • Random step count
    • Reliable upper limit
    • Minimum possible steps
    • Average execution time

  10. What does the term utility mean when applied to an algorithm?

    • Memory address
    • Practical usefulness
    • Line count
    • File extension

  11. For sorting five items, which algorithm is more efficient?

    • Twenty comparisons
    • Ten comparisons
    • Fifty comparisons
    • Four comparisons

  12. For an unsorted list used once, which algorithm type is more useful?

    • Sorted-only algorithm
    • Unrestricted search algorithm
    • Manual sorting step
    • Static array lookup

  13. Why should logical reasoning be used to compare algorithms?

    • To speed up code
    • To format text
    • To justify choices
    • To design graphics

  14. Binary search runs on the sorted list [2, 4, 6, 8, 10]. Which item is checked first?

    • 6
    • 8
    • 4
    • 2

  15. If n equals 10, which algorithm takes fewer steps?

    • Three hundred steps
    • One thousand steps
    • One hundred steps
    • Thirty steps

  16. Why is bubble sort inefficient for a million items?

    • Insufficient RAM
    • Network latency
    • Excessive comparisons
    • Syntax errors

  17. How is a correct algorithm that takes a long time described?

    • Correct but inefficient
    • Incorrect and fast
    • Invalid and slow
    • Buggy and optimal

  18. How many swaps does insertion sort need on an already sorted list?

    • Ten
    • One
    • Zero
    • Equal to items

  19. How should developers choose between algorithms for a database search?

    • Test realistic data
    • Pick the shortest
    • Use random choice
    • Guess the fastest

  20. Which search algorithm is best for a million sorted items?

    • Bubble search
    • Random search
    • Linear search
    • Binary search

All KS3 Computing quizzes