P1 Revison

P1 Revison

1. Wave Basics

   • Features
     • Amplitude
       • Rest position to crest
     • Wavelength
       • Crest to crest
     • Frequency
       • number of complete cycles per second
       • Hertz (Hz)
   • Speed = Frequency x Wavelength
     • m/s = Hz x m
   • Types
     • Transverse
       • right angle to direction of motion
       • Light, Radio & Water
     • Longitudinal
       • Same direction as wave is going
       • Sound, P waves

2. Wave Properties

   • Travel in straight lines
   • Reflection
     • Angle of incidence = Angle of reflection
     • Total Internal Reflection
   • Refraction
     • changing the speed, changes direction
   • diffraction
     • Waves spread out
       • When they pass
         • through a gap
         • an object

3. Communication

   • Electromagnetic waves
     • Radiowaves
       • Radio
       • Refracted in ionosphere
         • Long-Distance
       • TV, Mobile Phones
     • Microwaves
       • satellite communication
       • MobilePhones
     • Infrared
       • cooking
       • Remote controls
       • computers
       • security systems
       • Night Vision
       • Optical Fibre
     • Visable light
       • Codes
       • Optical Fibres
       • Lasers
         • Read digital info from CDs
           • Pits and Lands
     • Ultraviolet
       • Skin Cancer
         • Eye Problems
         • SPF (Sun Protection Factor)
         • Darker skin absorbs more UV
       • Ozone
         • CFCs
           • Now banned
         • Hole above Antarctica
     • X-Rays
     • Gamma rays
   • Wireless
     • portable
     • weather affects it
   • Wired
     • low set up cost
     • Easy & Cheap maintence

4. Saving Energy

   • Insulation
     • Loft Insulation
       • reduces conduction
       • Trapped air
     • Cavity Walls
       • Reduces Conduction & Convection
     • Double Glazing
       • Reduces Conduction
   • Efficiency
     • Efficiency = Useful Energy Output Total Energy Input

5. Seismic Waves

   • Earthquakes
     • P Waves
       • Longitudinal
       • Faster
         • Solid Inner Core
       • Travel through solids & liquids
       • Refract as density changes
         • Mantle to core
     • S Waves
       • Transverse
       • Travel through solids
         • Outer core is liquid
       • Slower
   • Seismographs