Transverse and longitudinal waves Cambridge International AS & A Level Physics revision
Not started
Learn it
In plain words
Shake a rope up and down and the wave runs along it while the rope itself moves across: that is transverse. Push a slinky back and forth and the coils bunch up and spread out along the line the wave is travelling: that is longitudinal. Light is the first kind and sound is the second.
4 things to know
- Transverse wave: the oscillations are at right angles to the direction the wave travels. Examples: all electromagnetic waves, waves on a string, ripples on water.
- Longitudinal wave: the oscillations are along the direction of travel. Sound is the main example. It travels as compressions (higher pressure, particles closer together) and rarefactions (lower pressure, particles further apart).
- Both kinds can be drawn as a displacement–distance or displacement–time graph. For a longitudinal wave the graph still plots how far each particle is from its rest position; it is not a picture of the wave.
- At the centre of a compression or a rarefaction the particles are at their rest positions, and that is where the pressure is furthest from normal.
Tips and tricks
- A displacement graph of a sound wave looks like a transverse wave. It isn't one: read the axes.
- The wavelength of a longitudinal wave is the distance between the centres of two neighbouring compressions.
It lands in your notebook with its questions as flashcards.
Transverse and longitudinal waves: 5 questions and answers
These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.
Which is a longitudinal wave?
The particles oscillate along the direction of travel.
In a transverse wave, how do the oscillations lie compared with the direction of travel?
That is the definition of transverse.
What is a rarefaction?
It is the opposite of a compression.
The centre of a compression is 0.25 m from the centre of the next rarefaction. What is the wavelength?
Compression to rarefaction is half a wavelength.
Which of these is a transverse wave?
All electromagnetic waves are transverse.
Quiz
5 questions
Tap an answer and you’ll see straight away whether it’s right, and why.
Worksheet
3 questions, 6 marks. Write your answers on paper, then check them.
Transverse and longitudinal waves
Cambridge International AS & A Level Physics 9702 · 6 marks · papermunch.org
Name ______________________________ Date ______________
State the difference between a transverse wave and a longitudinal wave.[2]
Show answerHide answer
In a transverse wave the oscillations are at right angles to the direction of travel of the wave; in a longitudinal wave they are parallel to it.
The centres of neighbouring compressions in a sound wave are 0.68 m apart. The speed of sound is 340 m/s. Find the frequency.[2]
Show answerHide answer
500 Hz. The wavelength is 0.68 m.
Describe a compression and a rarefaction in a sound wave.[2]
Show answerHide answer
A compression is a region where the particles are closer together than normal and the pressure is higher. A rarefaction is a region where they are further apart and the pressure is lower.
Answers: Transverse and longitudinal waves
- 1. In a transverse wave the oscillations are at right angles to the direction of travel of the wave; in a longitudinal wave they are parallel to it.
- 2. 500 Hz. The wavelength is 0.68 m.
- 3. A compression is a region where the particles are closer together than normal and the pressure is higher. A rarefaction is a region where they are further apart and the pressure is lower.