WAVES

WAVES

1. Waves

   • wave diagram
   • defonitions
   • transfer energy and infomation but NOT matter
   • TYPES
     • longitudinal
       • vibrations are parrallel to the direction of energy transfer
       • eg. sound, slinky spring
     • transverse
       • vibrations are at 90 to the direction of energy transfer
       • eg. all EM waves, ripple

2. EQUATIONS

   • wave speed= frequancy x wavelenght
   • T=1/F

3. Oscilloscopes

   • display
   • to find frequancy
     • find period by counting divitions
       • times by time base
         • use F=1/T

4. pitch and loudness

   • pitch=frequancy
   • loudness= amplitude

5. diffraction

   • the bending/ spreading of waves
     • through a gap or object
   • most diffraction when gap/object= wavelengh

6. signals

   • analogue
     • amplitude and frequency can vary
     • eg. watches, radios, old TV's, home phones
     • NOT good with interferance
   • Digital
     • a coded form of signal
       • takes values of 0 or 1
     • Advantages
       • LESS affected by interferance
       • interfeance not increased with volume
       • can carry more information (multiplexing)
       • can use weaker signals
       • easily processed by computers
       • quantisation allows more info by reducing finnity of signal
     • eg. mobiles, computers, Digital radios/TVs

7. The ELECTROMAGNETIC SPECTRUM

   • Remember My Instructions Visible Under X-ray Glasses
   • all travel at speed of light
   • Richard Of York Gave Battle In Vain
     • gamma rays
       • treatment of cancer, imaging, steralisation
       • radiation poisoning and cancer
   • radio waves
     • communication and broadcasting
     • eg. radios
   • microwaves
     • mobiles, TVs and satalights, microwave ovens
     • heat internal organs
   • infaread
     • heat and hot objects
     • thermal detection, remote controls, television signals
     • burns
   • visible light
     • cameras, video recorders
     • bright light can cause blindness
   • ultra-violet
     • the sun, UV lights
     • used for; tanning, steralisation, floressent lamps
   • X-Rays
     • imaging, treating canser
     • damage cells deep in body, cause canser

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