Flashcards
Waves Ch5
Flashcards do conjunto (51)
- 1Waves are a....a transfer of energy and information without matter
- 2Speed =Frequency x Wavelength
- 3Longitudinal Wavesvibrations are along the same direction as the direction of travel.
- 4Transverse Wavesvibrations are at right angles to the direction of travel
- 5A period of a wave is ....one cycle
- 6RefractionChange of speed and direction at a boundary
- 7DiffractionSpreading of waves around a obstacle
- 8ReflectionWhen a wave bounces off a surface. i=r
- 9Total Internal ReflectionAll energy reflects off inside of material at a boundary
- 10Progressive Waves ....and can be represented with a ...or...move through the medium
wave front or ray diagram - 11Progressive waves .... The particles oscillate or vibrate but....travel through a substance or space transferring energy.
do not move - 12When waves are in phase....they have the same direction, speed and displacement.
- 13When waves are out of phase...they are at different points in there cycle
- 14Phase difference is the....fraction of wave cycle between two points along a wave
- 15360 degrees =2pi
- 16Phase Difference in radians2π*Distance
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Wavelength - 17Mechanical WavesNeed a medium to travel through e.g. Seismic, sound, waves on a string
- 18Longitudinal waves have regions of ...... called ....high and low pressure
compressions
rarefraction - 19Sound travels fastest in....solids
- 20Transverse waves have ....electric and magnetic fields at right angles
- 21Light travels at3x10^8ms-1
- 22As you increase energy and frequency, wavelength....decreases
- 23Polarisation is when....the oscillations of one wave are confined to one plane
- 24Light reflecting off a surface can be polarised....when it is the right angle
- 25to get the best signal...the direction of the aerial matches the polarisation
- 26when filters are crossed at 90, ....all light is blocked
- 27Vertical Displacement of a wave=Amplitude*sin(2π*time/time of cycle)
- 28frequency =1/Time of One Cycle
- 29Electromagnetic Radiation varies in wavelength from ....to .....1 x 10^3 to 1 x 10^-12
- 30.....rays dont penetrate the atmosphereUltraviolet, XRays, and Gamma Rays
- 31Visible light has a wavelength of .....1*10^-6
- 32.....and ......are used for heatingMicrowaves
InfraRed - 33Ultraviolet is absorbed by skin causing .....tan and raising risk of skin cancer
- 34Refraction is the....change in direction when a wave travels from one medium to another
- 35During refraction,....frequency does not change but wavelength does
- 36Waves bend .......normal when they slow downtowards
- 37The refractive index is ....the ratio of speed between the two objects
- 38The RI of air is....1
- 39RI=1/speed of light in medium
- 40RI=sin i / sin r
- 41n1sin1 =n2sin2
- 42ri1/sin c
- 431n2=c1/c2 =1/2n1=n2/n1
- 44Total Internal Reflection is the...complete reflection of light at a boundary within a material with a higher ri than its surroundings
- 45When r = 90i is the critical angle
- 46sin x critical angle=n2/n1
- 47Optical Fibres....transmit light or infrared through glass or plastic fibre using TIR
- 48Step Index means that...there is a uniform RI across the core, and a smaller uniform RI cladding, which means only certain wavelengths are TIR
- 49Energy from signal is ....by fibre in which it travels therefore....and....absorbed
OF need low absorption
Need to be amplified - 50Modal DispersionSpread of signal due to rays taking different paths
- 51Material DispersionRI varies with wave length, therefore different wavelengths have different speeds.
Limits usable frequency
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- AS Physics FlashCards sobre Waves Ch5, criado por Andrew Stonehouse em 01-12-2017.
- Criado por
- Andrew Stonehouse
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