Waves Flashcards
What does a wave transfer?
Energy (from one place to another)
What causes a wave?
A vibration
What is the definition of a transverse wave?
The vibration causing a transverse wave is perpendicular to the direction of travel of the wave
What is the definition of a longitudinal wave?
The vibration causing a longitudinal wave is parallel to the direction of travel of the wave
Give 3 examples of longitudinal waves.
Sound, ultrasound and primary earthquake (P) waves
Give 3 examples of transverse waves.
Water waves, all EM waves and secondary earthquake (E) waves
What is a compression?
When particles in a longitudinal wave are closest together
What is a rarefaction?
When particles in a longitudinal wave are furthest apart
What is the amplitude?
The maximum displacement of a wave from its equilibrium position
What is the wavelength?
The distance from a point on one wave to the same point on the next wave
What is the frequency?
The number of waves passing a point each second
What are the units of wave speed, wavelength and frequency?
Wave speed - m/s, wavelength - m, frequency - Hz
What is the wave speed equation?
v = λ T
What speed do EM waves travel at?
300,000,000 m/s (speed of light)
What speed does sound travel at?
330 m/s
List the EM waves in order from longest to shortest wavelength
Radio, microwave, infra-red, visible, ultra-violet, x-ray, gamma
Which EM wave has the highest frequency?
Gamma
Which EM wave has the most energy?
Gamma
Which 3 EM waves are ionising?
Ultra-violet, x-ray and gamma
What happens when light travels from air into a glass block?
It refracts towards the normal as glass is more dense than air
What happens when light travels from a glass block into air?
It refracts away from the normal as air is less dense than glass
What is the law of reflection?
The angle of incidence is equal to the angle of reflection
What is a danger of ultra-violet radiation?
Increase the risk of skin cancer and cataracts
What is a danger of x-rays and gamma rays?
They are both ionising radiation that can cause the mutation of genes and cancer
What are radio waves used for?
TV and radio transmission
What are microwaves used for?
Satellite communication (they pass through atmosphere well) and for cooking food
What is infra-red used for?
Electric heaters, cooking food and infrared cameras
What is visible light used for?
Fibre optic communications, visible light microscopes
What is ultra-violet used for?
Detecting fake money, sun tanning
What are x-rays used for?
Medical imaging and security scanning
What are gamma rays used for?
Medical treatment (radiotherapy)
