Waves Flashcards
what is traverse wave and draw
oscillations are up + down but direction of energy transfer is sideways
example of tranverse wave and transfers
ripples on water surface transfers kinetic energy
what wave is tranverse wave
water wave
exmaple of tranverse wave on slinky
slinky tranverse wave represent ripple on water surface by the dot. It oscialltes up and down but not travel through air
what is longitudinal wave and draw
osicillations are parallel to the direction of energy transfer
example of longitudinal wave and transfers
sound waves travelling through air, transfers sound energy
what direction does longitduinal wave go
forward and back
what happens to air particles in longitudinal wave
vibrates, move side to side
what does longituidna wave show area of….
compression and rarefaction
example of longituidnla wave on slinky
slinkly represent sound wave travel, red dot is air particles. It oscillates side to side.
what is amplitude
the maximum displacement of a point on a wave away from its undisturbed point.
Loudness
what is wavelength
the distance from a point on one wave to equilivant point on the adjacent wave.
what is frequency
number of waves passing a point each second.
Pitchness
1hz=1wave
what is wave speed, unit
the speed at which the wave moves through the medium
V,m/s
a method to meausre the speed of sound wave in air
+ Problem and reduce
2 ppl seperated 50cm, A hold pair of cymbals, B hold timer.
1. B start timer when see A clash the cymbals
2. B stop timer when hear the sound clashing.
-every person differnt reaction time- reduce by more ppl hold timer and discord anamouls
-time between see clash and sound short- reduce by increase distancr
when can waves be aborbsed, transmitted and reflected
at boundary between 2 different materilas
what is refraction and reflected
waves changes direction when they pass from 1 materila to another.
wave may be reflected off the surface at the material.
what is absorbed and transmitted at boundary between 2 different materials
energy of wave abosrbed by material-no wave passes when happens.
wave sent out from source/pass through mateirl
ray diagram reflection of wave surface of mirror
incident ray = arrow shwo direction of ray
angle of incidence - measure angle betwen incident ray and normal
angle of reflection=angle of incidence
what is EM wave
electromagnetic waves are traverse wave that transfer energy of the source of the waves to an absorber.
example of EM wave
microwave oven, transfer energy from the source of oven, to the absorber the food.
what does EM wave form, and all type travel at
continuous spectrum, same velocity through air/vacuum.
who can detect the EM wave
human eyes only detect visible light - so detect liminated range of EM Wave
what is the range of EM wave
range is 10-15, to 10-4 metres
how does EM wave go from wavelength and frequency, and uses
long wave+low freq
RADIO WAVE - television,radio
MICROWAVE - cook food, satellite com
INFRARED- cook food, electric heater, tv remote control, camera
VISIBLE LIGHT-fibre optic comm
ULTRAVIOLET-energy efficient lamp, suntan
X-RAY-medical imaginary, treatment
GAMMA RAY- sterlise food, medical image+treatment
short wave+high freq
example of X-RAY on treatment and how
treat cancer skills by killing cancer cells
how does X-RAY work on entering human body
soft tissue transmit x-ray and bone absorbs
what is ultrasound
sound wave of frequencey above human range
what is human hearing range
20-2000HZ
ultrasound uses
-pre-natal scan
-destuction of kidney
-repair damage tissue cells
-remove plaque from teeth
what are hazardous effect on ultraviolet on human body tissue
-skin to age prematurely
-cancer
what are hazardous effect on x-ray and gamma ray
ionsing radiation causes the mutations of genes+cancer
what is ionising radiation
knock electrons off atoms when absorbed.
what does the effect depend on
size of dose and type of radiation
what are lens
form an image by refracting light
what is focal length
the distance from the lens to the principle focus
what are convex lens
parallel rays of light are brought to focus at the principle focus
what is the surface curved and thick at on convex lens
surface curved outwards
thicker centre than edge
what image does convex lens produce
real or virtual
what is real image and virtual
real - rays meet at a point and project shown on screen
virtual - rays do not meet only appear, so can’t see on screen
what does parallel ray light do through convex lens
passess through
draw convex ray diagram - both of it
what is concave lens
parallel rays of light enter lens and spread out
what is the surface curved and thick at on concave lens
surface curved inwards
thicker at edge than centre
what image does concave lens produce
virtual
what happens to lens at concave lens
and principle focus
diverge
lens does not focus the light at principle fous
what does parallel ray light do through concave lens
hits it
draw concave lens ray diagram - both of it
visible light spectrum order
long wave+low freq
-RED, ORANGE, YELLOW, GREEN, BLUE, INDIGO, VIOLET
short wave+high fre
what is specular reflection
what is boundary, is there image and reflection
reflection from a smooth surface in single direction
boundary is flat, produce image, see reflection on mirror
what is diffuse reflection, what is boundary, is there image and reflection
reflection from a rough surface causes scattering
boundary s bumpy, no image, cant see reflection
what is opaque
object cannot see through at all
colour of opaque object is determined by
which wavelenth of light are more strongly reflected or absorbed
object that transmit light are either
transparent or translucent
what is transparent
translucent
transp- can easily see through object (wine glass)
transl- scatter ray light so cant see through clearly
why is matt black surface good
it is best absorber and emitter of infrared radiation
what emits and absorbs infrared radiaton
all bodies (objects) no matter what temperature
the hotter the body…
more infrared radiatiton it radiates in given time
what is perfect black body
is an object that absorbs all the radiation incident on it
what is perfect black body best for…
possible emitter
object warmer/hotter than surroudning…
EXAMPLE
emit more radiation
-all black surface hotter than water
-cup of hot coffee
object cooler than surroudning…
EXAMPLE
absorbs more radiation
-dull black surface cooler than water
-burger on barque
object constant tempt then…
absorbs and emits radiation same time
what does wavelentgh and radition depend on
temperature of object
what is intensity
power of radiation
what is radiation
energy that move from one place to another
what is hazard to exposure infrared rediation
skin burns
diagram of glass block ray
- object
-incident ray - normal – to shwo direction chance, velocity decrease as light pass from air into glass
-wave slow down
-reflected ray – velocity increase as wave pass glass and back into air
what happend when in glass block,
wave speed down -
wave spped up -
bend toward normal
bend away from the normal
what is primary colour filter
what colur is it
only allow one of three colour to be transmitted
-red, green, blue
what is non-primary
what colour + what goes through
let through both wavelemtgh of light that same colour as filter
-indigo = blue and red yellow=red and green
convert concave ray diagram
-virtual, upright, smaller than image
convex ray diagram
-real, inverted(upside down), smaller than image
which particular colour and object appear depends on…
what does it determine aswell
- wavelentgh of light hitting it
-properties of that particualr object
determine if object absorbed,reflected and transmitted
