AQA AS Level Physics Paper 2, June 2023: Question 24

1 mark · Medium difficulty · Multiple Choice

Identify the phase difference and distance between adjacent antinodes for a stationary wave of wavelength lambda.

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Question

Multiple choice question 24 asking for the phase difference and distance between adjacent antinodes of a stationary wave of wavelength lambda, with four options A, B, C, and D presented in a table.
Question text

24 A stationary wave of wavelength λ is produced on a string.

What are the phase difference and the distance between adjacent antinodes?

[1 mark]

Phase difference Distance

π λ

A

π λ

B

λ

C π

λ

D π

Mark scheme

Show the mark scheme Mark scheme indicating the correct answer is D, with a phase difference of pi and a distance of lambda over 2.

π λ

24 D

How to answer it

Phase Difference and Distance Between Antinodes in Stationary Waves

What this question tests

This question tests your conceptual understanding of stationary wave profiles, specifically the spatial separation between adjacent antinodes (points of maximum amplitude) and the phase relationship between different points along a stationary wave.

Question 24 (Multiple Choice)

Exam Breakdown

✅ Correct Answer: D

Phase difference: π

Distance: λ / 2

Worth 1 mark

💡 Key Knowledge

  • All particles between adjacent nodes (i.e., within the same loop, bounded by nodes) are in phase with each other.
  • Since adjacent antinodes belong to adjacent loops separated by a single node, their displacements are always in opposite directions.
  • Opposite directions in wave motion correspond to a phase difference of π radians (180°).
  • The distance between two adjacent nodes is λ / 2 , and similarly, the distance between two adjacent antinodes is also λ / 2 .

🧠 Exam Technique

  • Sketch a quick mental image or rough diagram of a stationary wave (showing a full wave loop or multiple loops).
  • Identify the positions of the nodes (zero amplitude) and antinodes (maximum amplitude).
  • Recall key metric intervals: Node-to-node = λ / 2 , Antinode-to-antinode = λ / 2 , Node-to-antinode = λ / 4 .

❌ Common Errors

  • Confusing the distance between a node and an antinode ( λ / 4 ) with the distance between adjacent antinodes ( λ / 2 ).
  • Assuming points in a stationary wave can have arbitrary phase differences other than 0 or π (particles are either completely in phase or completely in antiphase).

Topics

Physics · 3.3 Waves

Question and mark scheme from the AQA AS Level Physics examination, Paper 2, June 2023. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.