Transverse and longitudinal waves
Cambridge A-Level Physics (9702) · Unit 7: Waves · 9 flashcards
Transverse and longitudinal waves is topic 7.2 in the Cambridge A-Level Physics (9702) syllabus , positioned in Unit 7 — Waves , alongside Progressive waves, Doppler effect for sound waves and Electromagnetic spectrum. In one line: In transverse waves, the oscillations are perpendicular to the direction of energy transfer (.
Marked as AS Level: examined at AS Level in Paper 1 (Multiple Choice), Paper 2 (AS Structured Questions) and Paper 3 (Advanced Practical Skills). The same content may also be assumed in Paper 4 (A Level Structured Questions).
The deck below contains 9 flashcards — 4 definitions and 5 key concepts — covering the precise wording mark schemes reward. Use the 4 definition cards to lock down command-word answers (define, state), then move on to the concept and calculation cards to handle explain, describe, calculate and compare questions.
The primary difference between transverse and longitudinal waves
In transverse waves, the oscillations are perpendicular to the direction of energy transfer (
What the Cambridge 9702 syllabus says
Official 2025-2027 spec · AS LevelThese are the exact learning outcomes Cambridge sets for this topic. The candidate is expected to be able to do each of these on the relevant paper.
- compare transverse and longitudinal waves
- analyse and interpret graphical representations of transverse and longitudinal waves
Cambridge syllabus keywords to use in your answers
These are the official Cambridge 9702 terms tagged to this section. Mark schemes credit responses that use the exact term — weave them into your answers verbatim rather than paraphrasing.
Tips to avoid common mistakes in Transverse and longitudinal waves
- › Specify wavelength as the distance between two adjacent wavefronts or the minimum distance between points in phase.
- › Distinguish between displacement (instantaneous) and amplitude (maximum). Nodes have zero amplitude and never move from the equilibrium position.
- › Always use the term 'adjacent' or specify the 'minimum distance' between two points in phase, such as adjacent wavefronts or crests.
- › Always refer to 'particle oscillations' being parallel to the 'direction of energy transfer' for longitudinal waves.
- › Define stationary waves as the superposition of two waves of the same frequency and amplitude traveling in opposite directions.
What is the primary difference between transverse and longitudinal waves?
In transverse waves, the oscillations are perpendicular to the direction of energy transfer (
Give an example of a transverse wave and describe the motion of particles within it.
Light waves are transverse waves. Particles (or, more accurately, fields) oscillate perpendicularly to the wave's direction of travel.
Describe how displacement and distance relate to a transverse wave's graphical representation.
In a displacement-distance graph for a transverse wave, the y-axis represents the displacement of the particles from their equilibrium position, and the x-axis represents the distance along the wave. This graph shows the wave's shape at a particular instant in time.
Describe how displacement and time relate to a transverse wave's graphical representation.
In a displacement-time graph for a transverse wave, the y-axis represents the displacement of a single particle from its equilibrium position, and the x-axis represents time. This graph shows how a single particle's displacement varies over time as the wave passes.
What do the peaks and troughs of a transverse wave represent in a displacement-distance graph?
The peaks represent the points of maximum positive displacement, while the troughs represent the points of maximum negative displacement from the equilibrium position.
How do compressions and rarefactions relate to longitudinal waves?
Compressions are regions of high density and pressure, where particles are close together. Rarefactions are regions of low density and pressure, where particles are spread apart.
Describe how displacement and distance relate to a longitudinal wave's graphical representation.
In a displacement-distance graph for a longitudinal wave, the y-axis represents the displacement of the particles from their equilibrium position, and the x-axis represents the distance along the wave. Compressions correspond to regions where the slope changes from positive to negative, and rarefactions correspond to regions where the slope changes from negative to positive.
How can the wavelength of a longitudinal wave be determined from a displacement-distance graph?
The wavelength is the distance between two successive compressions (or rarefactions) on the graph. This can be measured as the distance between two points where the displacement is at a maximum or minimum and the displacement is returning towards zero.
Describe the relationship between the frequency of a wave and its period.
Frequency (f) is the number of complete wave cycles that pass a point per unit time, and it is measured in Hertz (Hz). Period (T) is the time taken for one complete wave cycle. They are inversely proportional: f = 1/T
Review the material
Read full revision notes on Transverse and longitudinal waves — definitions, equations, common mistakes, and exam tips.
Read NotesMore topics in Unit 7 — Waves
Transverse and longitudinal waves sits alongside these A-Level Physics decks in the same syllabus unit. Each uses the same spaced-repetition system, so progress in one informs the next.
Key terms covered in this Transverse and longitudinal waves deck
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