Waves

Waves

1. Key Words

   • Frequency - Number of Waves per second
     • Measured in Hertz (HZ)
   • Amplitude - Height of a wave
     • Measured in decibels
   • Wavelength - distance from a corresponding point of a wave
     • Measured in Metres (M)
   • Compression - Region were vibrating particles are closer together
   • Rarefaction - Regions where particles are far apart

2. Types of Waves

   • Transverse Wave - Oscillations are perpendicular
   • Longitudinal Wave - Oscillations are parallel

3. Ultrasound

   • Sound that vibrates at frequencies above 20,000 Hz
   • Uses Of Ultrasound
     • Scanning of a foetus
     • Sonar
     • Industrial Imaging
     • Sterilisation

4. Seismic Waves

   • Types Of Seismic Waves
     • Surface Waves
       • Most destructive wave
     • S-Waves
       • More destructive than P-Waves
       • Slower than s-waves
       • Can't travel through liquids
       • Transverse Waves
     • P-Waves
       • Least destructive
       • Can refract
       • Longitudinal waves
   • Seismograph
     • Picks up the vibrations from an earthquake which vibrates the spring, moving the pen and drawing a seismograph on the drum

5. Reflection and Refraction

   • Angle of Incidence is equal to Angle of Reflection
   • When a wave reaches a boundary between two different materials, it can be reflected, transmitted or absorbed
   • The speed of a wave changes when it changes material. This can lead to refraction

6. Lenses

   • Rules Of Convex Lens
     • An incident ray travelling parallel to the axis refracts through the lens and passes through the principal focus on the other side
     • An incident ray passing through the centre of the lens carries on in the same diraction
   • Concave Lenses diverge rays
   • Convex lenses converge rays
   • Magnification - Image Size / Actual Size