P12

Cards (28)

  • Amplitude of a wave is the height of the wave crest or depth of a wave trough from midpoint of wave
  • The greater the amplitude of a wave, the more energy it carries
  • Wavelength of a wave is the distance from 1 crest to the next
  • Frequency of wave is number of crests passing a point in one second
  • Period of a wave is the time it takes for 1 wavelength to pass a point
  • The point an earthquake orignates from is called focus
  • The closest point on the earth's suraace to the focus is called the epicentre of the earthquake.
  • P-waves are longitudinal waves and cause initial tremors
  • P-waves refract at boundary between mantle and core
  • S-waves are transverse waves and travel more slowly than P-waves and cause tremors produced after first minute
  • S-waves cannot travel through liquid core of Earth
  • Both p-waves and s-waves bend as they travel through mantle because their speed gradually changes
  • L-waves travel more slowly than P and S waves and cause violent movement of earth's crust
  • L-waves travel only in earth's crust
  • Refraction happens as waves can change speed and wavelength as they cross boundary between diff substances
  • Mechanical waves travel through a medium e.g. sound waves and can be transverse or longitudinal
  • Electromagnetic waves can travel through a vacuum and all are transverse
  • Transverse waves are waves where the points along its length vibrate at 90 degrees to direction of energy transfer
  • Longitudinal waves are waves where points along its length vibrate parallel to direction of energy transfer and are made up of compressions and rarefactions
  • waves transfer energy and are used to transfer information too.
  • the direction in which the wave travels is the direction in which wave transfers energy
  • echo sounding uses high frequency sound waves to detect objects in deep water and measure water depth below a ship
  • Echo sounding works as pulses are reflected at sea bed and detected by reciever at same depth and total distance travelled by the wave is speed multipled by time and this would be halved
  • sound is caused by mechanical vibrations in a substance and travels as a wave.
  • sound waves cannot travel through vacuum
  • sound waves are longitudinal waves and can be reflected from hard, flat surfaces like walls to provide an echo
  • the pitch of a note depends on the frequency of the sound waves. the higher the frequency, the higher the pitch
  • the loudness of a sound depends on amplitude of the sound waves. the greater the amplitude, the more energy the wave carries and louder the sound