A student investigates waves on a stretched rope. The student moves one end of the rope up and down repeatedly to produce a transverse wave. Describe the key features of a transverse wave and explain how the rope moves as the wave travels along it.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (5 marks)
A transverse wave is one in which the oscillations of the rope are perpendicular to the direction of wave travel.
The rope therefore moves up and down (vertically) while the disturbance propagates horizontally along the rope.
The wave has distinct crests (peaks) and troughs (valleys). The amplitude is the maximum displacement of the rope from its rest (equilibrium) position. The wavelength is the distance between two successive points that are in phase, for example from crest to crest or trough to trough.
The rope therefore moves up and down (vertically) while the disturbance propagates horizontally along the rope.
The wave has distinct crests (peaks) and troughs (valleys). The amplitude is the maximum displacement of the rope from its rest (equilibrium) position. The wavelength is the distance between two successive points that are in phase, for example from crest to crest or trough to trough.
Examiner tips
- Use the word "transverse" and state that oscillations are perpendicular to the direction of travel.
- Mention both the vertical motion of the rope and the horizontal propagation of the disturbance.
- Include the terms crest, trough, amplitude and wavelength.
- Show the relationship between amplitude and maximum displacement from equilibrium.
Common mistakes
- Confusing transverse with longitudinal waves – forgetting that the motion is perpendicular.
- Omitting the definition of amplitude or wavelength.
- Using the wrong direction for the rope motion (e.g. horizontal instead of vertical).
Mark scheme (5 marks)
- A transverse wave is one where the vibrations (oscillations) are perpendicular (at right angles) to the direction of wave travel (energy transfer)
- The rope moves up and down (vertically) while the wave travels horizontally along the rope
- The wave has crests (peaks) and troughs
- The amplitude is the maximum displacement of the rope from its rest (equilibrium) position
- The wavelength is the distance between two successive points that are in phase (e.g. crest to crest or trough to trough)
Key terms in this question
Related
- All WJEC A-Level Physics (Wales) revision notes →
- How to answer a "Describe" question →
- Decode the mark scheme abbreviations →
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