Types of waves for AQA GCSE Physics
This page covers the following topics:
1. Transverse waves
2. Longitudinal waves
3. Categorising waves
4. Sound waves
5. Seismic waves
Transverse waves make the particles of the wave travel perpendicular to the direction of energy transfer. Examples of transverse waves include light waves and seismic S waves.
Longitudinal waves have particle oscillations that are parallel to the direction of energy transfer in the wave. Examples of longitudinal waves include sound waves and seismic P waves.
Different types of waves can be categorised depending on different characteristics: the presence of particles, the orientation of particle movement and the direction of energy transfer. The two main types of wave are electromagnetic and mechanical waves; mechanical waves can be broken down further into transverse, longitudinal and surface waves.
Sound waves are longitudinal waves; some frequencies can be heard by humans, but others are out of the range of human hearing.
Seismic waves are created by earthquakes, and they travel through the different layers of the earth. There are two types of Seismic waves: P waves, that are longitudinal, and S waves that are transverse.
P waves travel at approximately 7000 m/s. An earthquake happens and it causes P waves to occur, these are picked up from a seismometer 4000 km away. How long does it take for the P waves to be detected by the seismometer?
Time = Distance ÷ Speed, Time = 4000000 ÷ 7000 = 571 seconds = 9.5 minutes
Electromagnetic waves are an example of transverse waves. Name 3 types of electromagnetic waves.
any 3 from: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays
Explain how P and S waves provide evidence that the Earth’s core is liquid.
S waves are only able to travel through solids. When S waves travel through the Earth, they create a shadow zone which is created because S waves do not travel through the Earth’s core. Therefore, as the S waves do not travel through the Earth’s core, we know that it must be liquid.
Which of the following lists of waves only contain longitudinal waves?
A) sound waves, seismic P waves, light waves
B) sound waves, seismic S waves, ultrasound waves
C) sound waves, seismic P waves, ultrasound waves
C) sound waves, seismic P waves and ultrasound waves
The diagram shows a person standing outside a room where a TV is on. Explain why the person can hear the television, but not see it.
Sound waves are able to diffract around obstacles and corners, so the sound waves will still reach the person easily. Diffraction of light waves around of corners is not noticeable, therefore the person would not be able to see the television.
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