Paper 2 waves Flashcards
Properties of waves
A wave is a regular disturbance that carries energy from one place to another. Waves also carry information. WAVES DO NOT CARRY PARTICLES
Transverse waves
When the vibrations are at a right angle to the direction of the wave
Longitudinal wave
When the vibrations are parallel to the direction of the wave
compression
Where the particles are squashed together
rarefaction
Where the particles are spread out
Mechanical waves
Sound and water (can’t travel through a vacuum)
Electromagnetic waves
Light and infrared (can travel through a vacuum)
Peak and crest
Highest point on a wave
trough
Lowest point on a wave
amplitude
The height from the peak to the centre of the wave
Wavelength
Distance from a point on one wave to the equivalent point on the adjacent wave
frequency
How many waves pass by a pint every second or number of waves produced each second
Frequency= cycles/time
period (T)
How long it takes for one wave to pass a point in seconds
wavespeed =
Frequency x wavelength
Angle of incidence =
Angle of reflection
When light enters glass it bends
Towards the normal
When light leaves the glass it bends
Away from the normal
Why does sound travel fastest through solids
Because the particles are closer together so the vibrations are more easily passed from particle to particle so sound travels faster
The larger the amplitude of the wave
The louder the sound
The greater the number of waves across the oscilloscope trace
The higher the frequency and pitch
radiowaves
Uses: telecommunications, TV, radio
Dangers: none
Microwaves
Uses: telecommunications, cooking, RADAR
Dangers: can produce burns, cataracts, cancer?
Infrared
Uses: heating, cooking, TV remotes, night-vision
Dangers: can burn
Visible light
Uses: seeing
Dangers: eye damage from bright lights
Ultraviolet
Uses: discos, tanning salons, pollination
Dangers: skin cancer
X-ray
Uses: medical imagery, security
Dangers: cancer
Gamma rays
Uses: cancer treatment, observing the universe
Dangers: cancer
High frequency
Short wavelength, high energy
Low frequency
Long wavelength, low energy
Ultra sound waves
Waves which have a frequency higher than (20,000Hz)
Waves are partially reflected when they meet a boundary between 2 different media. time taken to do so determines the thickness
What can ultra sound be used for
Medical scans, industrial cleaning and non-destructive testing of materials
