Lesson 4.3.4.3

4.3.4.3 Binary tree search Quiz: AQA Computer Science, Unit 3

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.3.4.3, Binary tree search: 20 multiple choice questions for the AQA Computer Science (7517), Unit 3: Fundamentals of algorithms, written with Revision Ninja.

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The 20 questions

  1. What is the average time complexity of a binary tree search algorithm?

    • O(n)
    • O(1)
    • O(n^2)
    • O(log n)

  2. In a binary search tree, where are values smaller than a node stored?

    • Root node
    • Left subtree
    • Parent node
    • Right subtree

  3. What is the maximum number of child nodes any node in a binary tree can have?

    • Two
    • One
    • Three
    • Unlimited

  4. When searching a binary search tree, which path is taken if the target value exceeds the node?

    • Parent node
    • Root node
    • Left subtree
    • Right subtree

  5. What is the primary advantage of balanced binary tree search over linear search?

    • Constant time
    • Fewer comparisons
    • Lower memory usage
    • Simpler code

  6. A binary search tree is built by inserting 50, 30, 70, 20, 40, 60 and 80 in that order. How many comparisons are needed to find 60?

    • 2
    • 4
    • 3
    • 1

  7. In the same tree (50, 30, 70, 20, 40, 60, 80), how many comparisons are made searching for 35, which is not present?

    • 2
    • 4
    • 7
    • 3

  8. How many levels does the tree built from 50, 30, 70, 20, 40, 60 and 80 have, counting the root as level 1?

    • 4
    • 7
    • 2
    • 3

  9. Inserting elements in strictly ascending order into an unbalanced binary search tree produces what structure?

    • A cyclic graph
    • A linear chain
    • A balanced tree
    • A complete graph

  10. What is the height of a degenerate binary tree containing n nodes?

    • 1
    • log n
    • n
    • n^2

  11. A balanced binary search tree holds 1000 values. Approximately how many comparisons does a search need?

    • 1000
    • 10
    • 500
    • 100

  12. A partial binary search tree has root 50, a right child 70 whose left child is 60. How many comparisons are needed to conclude that 65 is absent?

    • 4
    • 2
    • 5
    • 3

  13. In a binary search tree built from 5, 3, 8, 1 and 4, what is the left child of 3?

    • 1
    • 8
    • 4
    • 5

  14. In the binary search tree built from 5, 3, 8, 1 and 4, how many comparisons are needed to find 4?

    • 4
    • 1
    • 3
    • 2

  15. A perfectly balanced binary search tree has n nodes. Which expression gives its approximate height?

    • n
    • n squared
    • log2(n)
    • n / 2

  16. What is the worst-case time complexity of searching an unbalanced binary tree?

    • O(n)
    • O(n^2)
    • O(1)
    • O(log n)

  17. What operational advantage does a binary search tree have over a sorted array?

    • Faster random access
    • Efficient insertion
    • Simpler traversal
    • Less memory used

  18. A binary search tree is built by inserting 8, 3, 10, 1, 6, 14, 4, 7 and 13 in that order. How many comparisons are needed to find 7?

    • 5
    • 3
    • 4
    • 2

  19. For the tree built from 8, 3, 10, 1, 6, 14, 4, 7 and 13, what is the in-order output?

    • 1, 3, 4, 6, 7, 8, 10, 13, 14
    • 8, 3, 1, 6, 4, 7, 10, 14, 13
    • 14, 13, 10, 8, 7, 6, 4, 3, 1
    • 1, 4, 3, 7, 6, 13, 14, 10, 8

  20. What happens to search efficiency when a binary tree degenerates into a single chain?

    • It becomes O(1)
    • It becomes O(n)
    • It remains O(log n)
    • It becomes O(n^2)

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