Explain the difference between a transverse wave and a longitudinal wave. In your answer, describe how the particles move in each type of wave relative to the direction the wave travels, and give one example of each.
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 particles of the medium vibrate perpendicular to the direction in which the wave energy travels. For example, a wave on a string or a light wave.
A longitudinal wave is one in which the particles vibrate parallel to the direction of wave travel, producing alternating regions of compression and rarefaction. For example, a sound wave in air.
A longitudinal wave is one in which the particles vibrate parallel to the direction of wave travel, producing alternating regions of compression and rarefaction. For example, a sound wave in air.
Examiner tips
- Use the word 'perpendicular' for transverse and 'parallel' for longitudinal.
- Mention compressions and rarefactions for longitudinal waves.
- Give a clear example of each type of wave.
- Keep the answer concise and to the point.
Common mistakes
- Confusing the direction of particle motion with the direction of wave travel.
- Using 'parallel' for a transverse wave or 'perpendicular' for a longitudinal wave.
- Failing to mention compressions/rarefactions for longitudinal waves.
Mark scheme (5 marks)
- In a transverse wave, particles oscillate/vibrate perpendicular (at right angles) to the direction of wave travel/energy transfer
- In a longitudinal wave, particles oscillate/vibrate parallel to (in the same direction as) the direction of wave travel/energy transfer
- Longitudinal wave described in terms of compressions and rarefactions
- A correct example of a transverse wave given
- A correct example of a longitudinal wave given
Key terms in this question
transverse wave · longitudinal wave
Related
- All WJEC A-Level Physics (Wales) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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