Waves Flashcards
what is a wave
a vibration that transfer energy from place to place w/o the transfer of matter
amplitude and wavelength
amplitude- max disturbance from a waves undisturbed postition
wavelength- distance between one point on a wave and the same point on the next wave
examples of different types of wave
EM
sound
seismic
transverse wave
vibration is perpendicular to direction of wave e.g EM, s
longitudinal wave
vibration is parallel to direction of wave e.g. sound, p
exhibit compression and rarefaction (particles are more further apart then average)
polarised wave
a wave that oscillates in 1 direction, materials can rotate the plane of polarisation
when light is reflected its partially polarised as intensity changes
frequency
number of waves produced by a source per second
1/ period
measured in hertz (Hz)
period
time taken for one whole wave to be produced
formula for wave speed
wave length (m) x frequency
what does 1 Hz mean
1 wave per second
seismic waves
S- type of transverse, they are slow and only travel through solids
P- type of longitudinal, fast, travel through liquids and solids
law of reflection
angle of incidence = angle of reflection
rough surfaces scatter light and sound in all directions but it still obeys the law of reflection
what causes echoes
reflection at a smooth surface
refraction
it is when a wave changes direction due to traveling through a medium of a different density
it happens due to a change in the wave speed
analogy of reflection and refraction
rippling of water waves
effect of refraction on speed frequency and wavelength
if moves through a denser medium light bends towards normal, lowering wave speed-frequency stays the same and wavelength decreases
if it moves through a less dense medium light bends away from the normal increasing wave speed- frequency stays the same and wavelength increases
effect of reflection on speed frequency and wavelength
no change to any
uses of ultrasound
sonar, scanning, animals
the doppler effect
the change in frequency when a source is moving
