Waves are a way of transferring energy from place to place.

Transverse waves

  • A wave that vibrates or oscillates at right angles to the direction which the energy or wave is moving.
  • Examples include light waves and waves travelling on the surface of water.

Longitudinal waves

  • A wave in which the vibrations or oscillations are along the direction which the energy of wave is moving.
  • An example includes a sound wave.

Wavelength= distance between a paticular point on the wave and the same point on the next wave. E.g crest-crest

Amplitude- Maximum number of movements from their resting or equilibrium position.

Frequency- number of waves produced each second. Measure in Hertz (Hz)

Wave speed= frequency x wavelength

Period= time taken for wave to complete one oscillation.  Period = 1/ frequency

Angle of incidence= line between the incoming light ray and the normal

Normal= a line at 90 degrees to the plane

Angle of reflection= angled between reflected light ray and normal 


  • All waves can be reflected, if they hit a flat or straight barrier, the angle in which they leave the barrier is equal to the angle at which they hit the barrier. This is described by the : Law of Reflected which states that : The angle of insidence is equal to the angle of reflection

Light refraction

  • Light is refracted when it travels from one medium to another
  • Light speeds up when entering a less optically dense medium
  • Light slows down as it enters a more optically dense medium

Sound waves

  • Longitudinal waves
  • Produced by vibrations of particles in a medium
  • The vibrations mean that the waves travel in a series of compressions and rarefractions
  • It can be absorbed, transmitted, refracted and reflected (echos)

Waves at a boundary

  • When waves travel from one medium to another, their speed and wavelength change(beause they are directly proportional) but their frequency stays the same. This is because the source is producing the same amount of oscillations per minute.

Electromagnetic Spectrum

  • The Electromagnetic Spectrum is a continious spectrum of waves, which includes the visible spectrum. At the one end of the spectrum, the waves have a very long wavelength whilst at the other end, the waves have a short wavelength and high frequency.
  • They all transfer energy
  • They are all transverse waves


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