waves Flashcards
amplitude
distance from rest point to crest
wavelength
full cycle of the wave
frequency
number of waves through a point each second
or the number of waves rom the source per second
transverse waves
move up and down 90 degrees to the direction of the wave
light and all em waves
waves on string
ripples on water
longitudinal waves
particles move parallel to direction of wave
sound waves and ultrasound
rarefraction
spread out
compressions
clumps on particles
wave speed =
frequency x length
drawing ray diagrams key points
the image is the same size
image is the same distance behind the mirror than in front
the image is virtual and upright
laterally inverted- the left and right side switch
diffraction
the waves spread out when they pass through gap or pass an object
amount of diffraction depends on…
the size of the gap relative to the length of the wave
small gap and long wave= lots of diffraction
diffraction rates
if the gap is the same as or smaller than the WAVELENGTH of a wave not amplitude
refraction key works
medium- the substance
incident ray
refracted ray
emergent ray
em spectrum
7 basic types but they merge into a continuous spectrum
vary between 10 to the -15 ——– 10 to the 4 in wavelength
em waves speed
travel at the same speed
higher frequency= shorter wavelength
different wavelengths= different properties
uses of long radiowaves
can be sent around world as they diffract around the earth- radio waves
can diffraction around hills and into tunnels
use of short wavelengths
cant diffract so have to be in direct line of transmitter
get around by reflecting off ionosphere- electrical charged layer of earth’s atmosphere
medium wavelengths can also be reflected- depending on weather
microwaves uses
satellites- can pass through watery atmosphere
microwaves health risks
heat up water in your cells
other uses of microwaves satellites
“remote sensing” satellites- used to see through clouds and track oil spills, icebergs movement and deforestation
infrared rays uses
wireless controllers- emit different patterns of rays for different commands
optical fibres- use infrared and visible light rays
pulses of rays are reflected off the sides of the core of the fibre very quickly
cameras
lens used to focus light onto a light sensitive film or electronic sensor
the lens APERTURE controls how much light enters the camera
shutter speed determines the exposure to the light
sound waves causes
vibrating through objects
heard when travelling through someone’s inner ear and reaches the eardrum
denser the medium- the faster the object travels through
sound cant travel in space
higher frequency =
higher pitch
frequency= number of complete vibrations per second
higher amplitude =
louder the sound
