Waves Flashcards
Transverse waves
A wave for which the oscillations are perpendicular to the direction of energy transfer
Longitudinal waves
A wave for which the oscillations are parallel to the direction of energy transfer
Give 2 examples of a transverse wave
- Electromagnetic waves
- Seismic S waves
Give 2 examples of longitudinal waves
- Sound waves
- Seismic P waves
What are the two parts of a longitudinal wave called?
-Compressions
-Rarefractions
Amplitude of a wave
The distance from the centre line (or the still position) to the top of a crest or to the bottom of a trough
Wavelength of a wave
The distance from a point on one wave to the equivalent point on the adjacent wave (peak to peak, or trough to trough)
Frequency of a wave
The number of waves passing a point each second (Hz)
What is meant by a frequency of 200Hz
200 waves pass a given point each second
How do sound waves travel through a solid
The particles in a solid vibrate and transfer kinetic energy through the material
What is the frequency range of human hearing
20Hz - 20kHz
What natural event causes seismic waves to be produced? What types are produced?
-Earthquakes
-Produce P Waves and S-waves
Compare P-waves and S-Waves. (4 Marks)
- P-waves are longitudinal that travel at different speeds through solids and liquids
- S-waves are transverse seismic waves that cannot travel through a liquid
Suggest how seismic waves could give us information about the Earth’s core.
- Change in speed of the waves
- Waves reflected
- Waves refracted
- Waves altered by density OR solid state
- Waves more differenly through solids and liquids
What technique is used to detect objects in deep water and measure water depth?
- Echo sounding
- High frequency sound waves are emitted, reflected and detected
- Time difference between emission and detection, alongside wave speed are used to calculate distances
Order the types of electromagnetic radiation from lowest to highest frequency
Radio waves
Microwaves
Infrared
Visible light
Ultraviolet
X rays
Gamma rays
How do the speeds of EM radiation differ in a vacuum and in air?
They all travel at the same speed in a vacuum and in air
What property of waves in different mediums cause refractions
- Velocity
- Wave speed is slower in denser materials, causing refraction
In which direction do waves refract when entering a denser medium
- Bend towards the normal
- The angle of refraction is less than the angle of incidence
Where do gamma rays originate from
Changes in the nuclei of atoms
What are the health effects of ultraviolet waves
- Can cause the skin to age prematurely
- This can increase the risk of developing skin cancer
What health effects can X-rays and gamma rays cause?
- They are ionising radiation so can cause mutations in genes
- They can lead to increased risk of developing various cancers
Uses for infrared radiation
- Electric heaters
- Infrared cameras
- Cooking food
Give two practical uses for microwave radiation
- Satellite communications
- Cooking food
