Waves

Waves

1. wave proprties

   • parts of a wave
     • amplitude = 1/2 the height
     • wavelength is the distance from one crest to the next
     • The frequency is the amount of full waves per second
     • The period of a wave is 1/frequency
   • Transverse
     • Particles vibrate perpendicular to the direction of energy travel
     • EM radiation
   • Longitudinal
     • Particles vibrate parallel to the direction of energy transfer
     • sound waves
   • reflection
     • Angle of incidence = angle of reflection
     • specular reflection is when a wave is reflected in a single direction on a smooth surface
     • Diffuse reflection occurs when waves are scattered in many directions on a rough surface
   • refraction
     • waves bent towards the normal when going into a denser substance and away from it when going into a less dense substance

2. EM radiation

   • All are transverse
   • Radio waves
     • Generates alternating currents in metals
   • Microwaves
     • can penetrate the atmsophere so are used for communicating with satelites
   • Infra-red
     • used in remote controls
   • Visible light
     • optical fibres
   • Ultraviolet
     • causes tans
   • X-ray
     • self-explanatory
   • gamma rays
     • Ionising radiation so can be used to sterilise surgical tools
   • <-- increasing wavelength --- increasing frequency -->