Waves

Waves

1. Types of Wave

   • Transverse
     • In a transverse wave, the oscillations and the direction of energy transfer are perpendicular.
       • All electromagnetic waves are transverse waves.
   • Longitudinal
     • In a longitudinal wave, the oscillations and the direction of energy transfer are parralel.
       • Sound is a longitudinal wave.

2. Measurements in a wave.

   • Velocity = Frequency x Wavelength
     • Wavelength (m) = The distance between 2 like points in a wave. (eg a trough and a trough)
     • Velocity (m/s)= The speed of the wave.
     • Frequency (Hz) = The number of complete waves passing a point in a lesson.

3. Electromagnetic Waves

   • All electromagnetic waves are transverse waves and travel at a speed of 300,000,000m/s.

4. Sound

   • Sound is a longitudinal wave.
     • Sound travels by the vibration of particles and so can't travel through a vacuum.
       • The pitch of a sound, how high or low it is, is determined by the frequency of the wave.
         • Humans can hear sounds in the range of 20Hz to 20KHz

5. A wave can be Reflected, Refracted and Diffracted.

   • Reflection
     • Reflection is when a wave hits a surface and is not absorbed by the surface. Angle of incidence=Angle of reflection.
   • Diffraction
     • Diffraction is the spreading out of of a wave when they pass an edge. Diffraction is greatest when the wavelength and the gap size is the same.
   • Refraction
     • When a wave changes medium, it may change direction. This can only occur is the wave enters the medium at an angle. The wave hits the surface and bends towards the normal. Angle of incidence > angle of refraction