Waves

• describe a transverse wave


  vibrations are at a right angle to direction of energy transfer e.g. light
• describe a longitudinal wave

  vibrations are parallel to direction of energy transfer e.g. sound
• what is the wavelength

  distance between two similar points of a wave
• what is the amplitude

  maximum displacement from rest
• what is the frequency

  number of cycles of a wave that occurs in one second
• what happens to water waves as they move from deep to shallow water

  speed and wavelength decreases from deep to shallow, they are proportional from each other. Frequency is constant.
• name the ionising parts of the EM spectrum

  ultra violet, X ray and gamma rays, able to interact with atoms to damage cells
• what are the regions of the electromagnetic spectrum

  radio waves, microwaves, infra red, visible, ultraviolet, X rays, gamma rays
• what are the features of em

  . radio waves have the longest wavelength and lowest frequency.

  . gamma rays have the shortest wavelength and highest frequency.

  . high frequencies transmit high energies
• what do all the regions of em spectrum have in common

  all transverse waves, they all travel at the same speed in a vacuum and transfer energy
• what is a geosynchronous satellite

  . orbit time of 24 hours

  . orbit only returns to exactly the same position in the sky after a period of one day.
• what is a geostationary satellite

  .orbit returns to same point in the sky at the same time each day

  . base station can be in constant communication with a geostationary satellite but only once every 24 hours with geosynchronous satellite.
• what to remember when calculating height of a satellite

  signal travels double the orbit height