waves Flashcards
what are the 2 types of waves?
transverse and longitudinal
what is a transverse wave?
when the particles of the medium move at right angles to the direction of travel of the wave
what examples of transverse waves are there?
surface waves and electromagnetic waves
what is a longitudinal wave?
the particles of the medium vibrate parallel to the direction of the wave
what examples of longitudinal waves?
sound waves travelling through a material
what happens to the size of the wave as it travels along in a transverse wave?
it decreases
what is a compression?
where the coil is close together
what is a rarefaction?
where the coil is spread out
what is the wavelength?
the distance from the start of one wave to the next
what is a crest or trough?
the top or bottom of the wave
what is wavelength measured in?
metres
what is the amplitude?
the maximum distance from the centre of the wave tp the top or bottom
what is amplitude half of?
the height of the wave
what is amplitude measured in?
metres
what is frequency?
the number of waves in 1 second
what is frequency measured in?
hertz (Hz)
what are good surfaces for reflection?
flat and shiny
what is the 90 degree to the mirror called?
the normal
what is the light ray that hits the mirror called?
incident ray
what is the light ray which bounces off the mirror?
reflected ray
what is the law of reflection?
angle of incidence = angle of reflection
what is the same after reflection?
speed, frequency and wavelength
what changes after reflection?
wave direction
what happens when light travels from air to glass?
light bends towards the normal
why does light bend as it passes from air to glass?
slows down
what happens when light travels from glass to air?
light bends away from the normal
why does light bend when it passes from glass to air?
speeds up
what does refraction mean?
change in direction
what is the same after refraction?
frequency
what is different after refraction?
speed, wavelength and direction
the higher the density the slower the…
light travels
what is the law of refraction?
angle of incidence is greater than the angle of reflection
what is unusual about electromagnetic waves?
they can travel through a vacuum
what are similar about electromagnetic waves?
they travel at the speed of light and they can all travel through a vacuum and are all transverse waves
what are the 7 waves in the electromagnetic spectrum?
radio waves microwaves infra-red radiation visible light ultraviolet x-rays gamma rays
what are radio waves used for?
transmitters in Aerials
what are visible light and infra-red waves used for?
optical fibres
what are microwaves used for?
mobile phone communication
what is a satellite?
any object that orbits a planet
what are natural satellites?
moon and plants that have moons
what are artificial satellites?
man made objects put into space
what are uses of satellites?
communication
weather forecasting
navigation
what is a geosynchronous satellite?
has an orbit time of 24 hours and stays above the same ground position
why does a geosynchronous satellite stay in a fixed position?
because it orbits in 24 hours which is the same time it takes for the earth to spin once
what are the disadvantages of satellites?
they are affected by weather
what are the advantages of optical fibres?
not affected by weather and are much quicker than satellites
