9.1 Waves Flashcards
Wavelength unit
metres, m
Frequency unit
Hertz, Hz
Time period unit
Seconds, s
Wavespeed unit
Metres per second, m/s
What do waves transfer?
Waves transfer energy
What dont waves transfer?
They dont transfer matter
What do waves travel through?
Waves travel through a medium. Each part will oscillate about an equilibrium position
What is special about electromagnetic waves?
Light does nit require a medium
What is the speed of light?
300,000,000 m/s
What is a longitudinal wave?
The medium oscillates parallel to the direction of energy transfer
What is an example of a longitudinal wave?
Sound waves
What is a transverse wave?
The medium oscillates perpendicular to the direction of energy transfer
Transverse wave example
Light
What is wavelength?
The distance from one point in a wave to the same point on the next
What is the time period?
The time for a wave to complete one cycle
What is frequency?
The number of waves produced per second
What is amplitude?
The maximum displacement of the medium from equilibrium position
What is compression?
The hugh pressuere area, where the medium is pushed together
What is rarefaction?
Medium is spread out in a longitudinal wave
Equation that links time period to frequency
T= 1/ f
f= 1/T
Equation that links frequency to wavelength to wave speed
Wavespeed= frequency x wavelength
Difference between T and f
T= time for each wave, f= number of waves fer second in Hz
What determines the volume of a wave?
The amplitude of a sound wave determines the volume, taller the louder
What determines the pitch of a sound?
The frequency of a sound wave determines thw pitch, more frequent the higher
What is the sppeed of sound in air?
330 m/s
What is the human audiable range?
20- 20000Hz
What is the name for above the audible range.
Ultrasound
What is the name for below the audible range
Infra sound
What matter does sound travel fastest in ?
Solid, than liquid than gas
How does a transmitter and reciever use an uktra sound.
- ultrasound wave sent by transmitter
- reciever listens for returning sound waves.
- time to echo and the speed kf sound in the mother used to calculate the total distance travelled by sound.
The distance is halved to find the location of baby
What is better ulta sound kr x rays.
Ultra sound is not ionising so is safer, but the image is low definition and less clear than an xray
What is the electro magnetic spectrum?
Radiowaves
Microwaves
Infrared radiation
Visible light
Ultra violet
X-rays
Gamma waves
Use of inrared waves?
used to transfer thermal energy to grill food
Use of ultra violet light
Absorbed by skin, too much exposure spcauses sunburn,
Can be absorbed by bacteris to sterilise equipment,
Absorbed by fluorescent ink in security tagging
Use of an xray
Transmits through soft tissue, but absorbed by bone to produce a medical image(absorbed by protective lead apron)
Can be absorbed by DNA ionising it, risks of cancer
What is the doppler effect?
The doppler effect is the apparent shift in wavelength/ frequency of waves from a source moving relative to an observer
What happens as source moves towards an observer
Sound shifts to high pitched, light appears to blue shift
What happens as source mives away from observer
Light red shufts, sound shifts to a lower pitch
