AQA GSCE Phsyics 3

• Sound travels as a wave
• it is caused by objects that vibrates
• They can reflect and refract
• Audible to human ear is 20 - 20 000Hz
• It can not travel in vaccum
• More waves = high frequency = higher pitch
• the amplitude increase (taller) = the loudness increases
• A clear pure sound produces a smooth rounded waveform called Sine Wave

Ultra Sound 

• Like there are electomagnetic radiation with frequenies we can nto see likewise there are sound waves that we cannot hear.
• It has several uses
• Ultra Sound has a higher frequency than the upper limit of a human
• Electronic systems produce ultrasound waves .  

 . 

• It usually/partially reflects when the boundaries meet between two different mediums
• The time taken that it takes to return back to the detector ... that will show how far the boundary is.
• Given the speed we can work out the distance between the boundaries
• Given the frequency and wavelength of the ultrasound you can wok out the speed.
  • Speed (m/s) = Freq (Hz) x Wavelength (m)
• USES
  • Extremely effective at removing dirt.
  • can be directed to very precise places
  • clean delicate mechanisms wihout needing to dismantle
  • MEDICINES
    • iT IS SAFER THAN X-RAYS