Physics

Physics

1. Waves

   • Longitudinal waves
     • A longitudinal wave is one in which the particles vibrate parallel to the direction in which the wave is travelling
     • Sound waves- the molecules of air around the vibrating cone cause a series of compressions and refractions through the air as the particles vibrate.
       • Slinky spring waves- when the spring is moved backwards and forwards parallel to the stretched spring
         • Ultrasound waves- used to see the foetus in a mother's stomach
   • Transverse waves
     • In a Transverse wave the vibrations are at 90' or perpendicular to the direction in which the wave is travelling
     • Water waves- has a horizontal motion
       • Electromagnetic waves- light or x-rays
         • Slinky spring waves- when the spring is moved up and down
   • The frequency of a wave is the number of complete waves passing a fixed point in a second. Measured in units called 'hertz'
     • Frequency= no. of waves divide by time (sec)
   • The wavelength of a wave is the distance between two consecutive crests or troughs. Measured in 'metres'
     • Wavelength= distance between consecutive waves e.g. wavelength = 50cm divide by 2 waves
   • The amplitude of a wave is the greatest displacement of the wave from its undisturbed position. Measured in 'metres' and is a metre of how much energy is carried by the wave.
     • Amplitude= 1/2 x distance from crest to trough