Studied by 6 peoplewaves
a way of transferring energy from place to place without matter by oscillations about a fixed point
two types of waves
longitudinal
transverse
transverse waves
waves where the points along its length vibrate at 90 degrees to the direction of energy transfer
features of transverse waves
have peaks and troughs
vibrate 90 degrees to the direction of energy transfer
transfer energy but not particles
cannot move in gas
electromagnetic waves can move in a vacuum
constant density and pressure
peak/crest
highest point on the wave above the rest position
trough
lowest point on the wave below the rest position
transverse waves - 4 examples
ripples on water
vibrations in a guitar string
s-waves
EM waves
longitudinal waves
waves where the points along its length vibrate parallel to the direction of energy transfer
features of longitudinal waves
have compressions and rarefactions
parallel to direction of energy transfer
transfer energy but not particles
move in all 3 states of matter
cannot move in a vacuum
changes in density and pressure
compressions
close together
rarefaction
far apart
longitudinal waves - 3 examples
sound waves
p-waves
pressure waves
amplitude (A)
distance from the undisturbed position to the peak or trough of a wave
unit for amplitude
metres
wavelength
distance from one point on the wave to the same point on the next wave
wavelength - transverse waves
measured from one peak to the next peak
wavelength - longitudinal waves
measured from the centre of one compression to the centre of the next
symbol for wavelength
λ (lambda)
unit for wavelength
metres
frequency (f)
number of waves passing a point in a second
unit for frequency
hertz (Hz)
time period (T)
time taken for a single wave to pass a point
unit for time period
seconds
wavefronts
created by overlapping lots of different waves and represented by a line where all the vibrations are in phase and the same distance from the source
wavefront - ray
arrow showing the direction the wave is moving
wavefront - wavelength
space between each wavefront
wavefronts close together
short wavelength
wavefronts far apart
long wavelength
relationship between the speed, frequency and wavelength of a wave
wave speed = frequency x wavelength
unit for wave speed
m/s
relationship between frequency and time period
frequency = 1/ timeperiod
1 kHz to Hz
1 kHz = 1000 Hz
doppler effect
change in wavelength and frequency of a wave emitted by a moving source
doppler effect - wave source moving towards the observer
observed frequency increases
observed wavelength decreases
doppler effect - wave source moving away from the observer
observed frequency decreases
observed wavelength increases
reflection
a wave hits a boundary between two media and does not pass through, but instead stays in the original medium
refraction
a wave passes a boundary between two different transparent media and undergoes a change in direction
sound waves
vibration of air molecules
what happens to a sound wave when it comes into contact with a solid
vibrations transfer to the solid
are sound waves longitudinal or transverse
longitudinal
reflection of sound waves
echo
electromagnetic waves
transverse waves that transfer energy from the source of the waves to an absorber
properties of EM waves
transverse
travel through a vacuum at the same speed
Note
Flashcard