Waves Flashcards
What is a transverse wave?
A transverse wave is a type of wave where the particles in the medium vibrate at right angles (perpendicular) to the direction the wave is travelling.
What is a longitudinal wave?
A longitudinal wave is a type of wave where the particles of the medium vibrate parallel to the direction the wave is travelling.
Give an example of a transverse wave
Light waves, water waves
Give an example of a longitudinal wave
Sound waves
What is the wavelength?
Distance between two corresponding points (e.g. crest to crest), measured in metres (m) Symbol λ
What is the amplitude?
Maximum displacement from the rest position – related to energy, measured in metres (m) Symbol A
What is the frequency?
Number of waves passing a point per second, measured in hertz (Hz) Symbol f
What is the period?
Time for one wave to pass a point. T = 1/f. Measured in seconds, s. Symbol T.
What is the wave speed?
How fast the wave moves. v = f × λ. Measured in m/s. Symbol v
What is the wave equation?
v=f×λ
v = speed (m/s)
f = frequency (Hz)
λ = wavelength (m)
What is the law of reflection?
Angle of incidence = Angle of reflection
Occurs with sound, light, and water waves.
The wave bounces off a surface.
What is refraction?
When a wave changes speed due to moving from one material to another (e.g. air to glass).
This causes it to change direction (bend).
How does refraction affect a wave in a slower material?
wave slows down and bends towards the normal.
How does refraction affect a wave in a faster material?
wave speeds up and bends away from the normal.
What is diffraction?
when a wave spreads out after passing through a gap or going around an obstacle.
When is diffraction most noticeable?
when the wavelength is similar in size to the gap or obstacle.
What can sound waves travel through?
Travel through solids, liquids, and gases, but not vacuum.
What is the speed of sound in air?
340m/s
Are waves from the electromagnetic spectrum transverse or longitudinal?
Transverse
What is the speed of light in a vacuum?
3x10^8m/s
Electromagnetic spectrum in order of increasing frequency?
Radio Waves, Microwaves, Infrared, Visible Light, Ultraviolet, X-rays, Gamma rays
Application of radio waves
radio and television signals
Application of microwaves
communications
Application of infrared
thermal imaging
