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Physics - Waves - Coggle Diagram
Physics - Waves
Transverse and Longitudinal
Waves transfer energy in the direction they are travelling
Properties
Amplitude
Maximum displacement of a point on the wave from its unturned position
Wavelength
Distance between the same point on two adjacent waves e.g two peaks
m
Frequency
Number of complete waves passing a certain point per second
Hz
Period
time taken for one full cycle if a wave
Transverse Waves
Waves vibrate
perpendicular
to direction of energy transfer
Electromagnetic wave
LIGHT
Water ripples
Longitudinal Waves
Sound
Wave vibrate
parallel
to the direction of energy transfer
Wave speed (m/s) = Frequency (Hz) x Wavelength (m)
Refraction
Wave changes direction at a boundary
crosses boundary
slows down
towards normal
speeds up
away from normal
wavelength changes
frequency stay same
optical density
how quickly light travels through
higher
slower
hits different medium at angle
Ray diagram
Electromagnetic Waves
Transverse waves that transfer energy from a source to an absorber
vibrations of electric and magnetic fields
all EM waves travel through a vacuum at the same speed
different speeds in different materials
Continuous spectrum
radio waves
microwaves
infrared
visible light
ultraviolet
x-rays
gamma rays
long wavelength low frequency
short wavelength high frequency
Uses
Visible Light
fibre optic cables
astronomy
Ultra-violet
sun
fluorescence
sterilising water
Radio
radio
TV
WiFi
Microwave
cooking
long distance and space communications
Infra-red
heating/cooking
cameras can measure heat
remote controls
X-rays
medical scanning
airport security
Imaging
Gamma
detect leaks
sterilising medical equipment
treating cancer
Dangers
Radio
none
too low energy
Microwave
only at certain frequencies and power
blood to boil and kill cells
Infra-red
heat can burn
Visible
lasers or direct sunlight can damage eyes
Ultra-violet
increase chances of cancer (skin)
X-rays
increase chances of cancer
Gamma
increase chances of cancer
Reflection
Angle of Incidence = Angle of Reflection
normal
perpendicular to point of incidence
angle of incidence
between incoming ray and normal
angle of reflection
between reflected ray and normal
when waves arrive at a boundary between 2 different materials
Absorption
energy is transferred to energy stores
Transmission
waves carry on travelling through new material
leads to refraction
Reflection
waves bounce back off boundary
Specular
reflected in single direction by a smooth surface
light reflecting off mirror
Diffuse
reflected by rough surface
rays are scattered in different directions
normal is different
surface appears matte
Required Practicals
Vibrating String
Water ripples