Year 10 Physics [3]

Year 10 Physics [3]

1. general waves

   • transverse
     • vibrate perpendicular to direction traveling
   • longitudinal
     • vibrate along direction of wave
   • frequency (Hz)
     • 1/time(s)
     • wave speed, v (m/s) = frequency (Hz) x wavelength, λ (m)

2. properties

   • reflection
     • angle i = angle r
     • concave barrier
       • waves converge
     • convex barrier
       • waves diverge
   • diffraction
     • large gap
       • mostly same direction
     • small gap
       • change in direction )))
   • refraction
     • (optically) + dense to - dense medium
     • change in direction at normal line

3. electromagnetic spectrum

   • properties
     • transverse
     • transfer energy
     • speed of light in a vacuum
     • can be reflected, diffr...
   • radio waves
     • longest, least energy
       • communication
     • microwaves
       • cooks from inside (H2O absorb microwaves)
         • satellites
       • infra-red
         • hotter object, +if radiation emitted
           • remotes
         • visible light
           • roygbiv
             • optical fibres, medicine
           • ultraviolet light
             • emitted by sun
               • ozone absorbs uv
                 • too much can cause cancer
             • x ray
               • pass through tissue not bone:medicine
                 • too much:cancer
               • gamma ray
                 • sterilise food/medical
                   • can cause mutation in genes
                     • but can also cure cancer

4. signals

   • digital
     • use of binary
   • analogue
     • info converted into electric currents
     • if amplified, so is background