Waves

• what is a transverse wave ?

  • has peaks and troughs
  • the oscillations are perpendicular to the direction of energy transfer
  • e.g water ripples
• what is a longitudinal wave ?

  • a wave with rarefactions and compressions
  • the oscillations are parallel to the direction of energy transfer
  • e.g sound waves
• what are the 7 waves in the electromagnetic spectrum ?

  • radio waves
  • micro waves
  • infrared radiation
  • visible light
  • ultra violet
  • x-rays
  • gamma rays
• what do electromagnetic waves have in common ?

  • all are transverse waves
  • all travel at the same speed through a vacuum
  • x-rays, gamma rays and ultra violet are all ionising radiations
• which wave has the longest wavelength and lowest frequency ?

  radio waves
• which wave has the shortestcwave length and highest frequency ?

  gamma rays
• what is a refraction ?

  waves changing direction at a boundary
• what is a refraction like ?

  • bends toward the normal
  • higher the density the larger the refraction
• describe a radio wave ?

  • can be produced by using an alternating current in an electrical circuit
  • object that charges electrons oscillate to create the wave this is known as a transmitter
  • longest wave length
  • can be received over long distances
• what are the uses for radio waves ?

  • bluetooth
  • TV & FM radio
• what are the uses for microwaves ?

  • satellites
  • microwave ovens
• what are the uses for infrared radiation ?

  • infrared cameras
  • electric heaters
• what are the uses for visible light ?

  • optical fibres to transmit data
• what are the uses for ultraviolet ?

  • tanning bed
  • sterilisation
  • security pens
• what are the uses for x-rays ?

  • medical imaging
  • radiotherapy
• what are the uses for gamma rays ?

  • radio therapy
• what are the dangers of ultraviolet ?

  • skin cancer
  • skin can age prematurely
  • blindness
• what are the dangers of x-rays ?

  • can cause cells to mutate
  • can cause cancers
• what are the dangers of gamma rays ?

  • ionisation (although weakly ionising)
  • cells can mutate
  • cancer
• what does the risk depend on ?

  the amount of radiation absorbed
• how many millisieverts are in one sievert ?

  1000