physics- waves

• Transverse

  Wave in which the oscillations are perpendicular to the direction of energy transfer.
• Longitudinal

  Wave in which the oscillations are parallel to the direction of energy transfer.
• Amplitude


  The maximum displacement of a point on a wave away from its undisturbed position.
• Frequency


  The number of waves passing a point each second. Often represented by 'f'.
• Wavelength


  The distance from a point on one wave to the equivalent point on the adjacent wave. Often represented by 'λ'. Its unit is metres.
• Wave speed


  The speed at which the energy is transferred (or the wave moves) through the medium.
• Specular reflection


  Reflection from a smooth surface in a single direction.
• Diffuse reflection


  Reflection from a rough surface causing scattering.
• Refraction


  The change of direction of a wave as it passes across a boundary between two different media.
• Mechanical Waves


  Waves which require a substance (medium) to travel through.
• Electromagnetic waves


  Waves that do not need a substance (medium) to travel through. They can travel through a vacuum.
• Peak


  The top part of a wave.
• Trough


  The bottom part of a wave.
• Irradiation


  Exposure of an object to ionizing radiation
• Transverse Waves


  Waves in which the vibrations are perpendicular (at 90˚) to the direction energy is transferred.
• Longitudinal Waves


  Waves in which the vibrations are parallel to (in the same direction as) the direction energy is transferred.
• Compressions


  Parts of a longitudinal wave which are squeezed together, so that they have a higher density.
• Rarefactions


  Parts of a longitudinal wave which are stretched or spread apart, so that they have a lower density.
• Oscillation


  Movement of a particle back and forth - another word for vibration.
• Parallel


  In the same direction (0°).
• Perpendicular


  At right angles (90°).
• Crests


  Peaks of a transverse wave.
• Troughs


  Bottom most parts of a transverse wave.
• Amplitude


  The height of a wave crest or a wave trough of a transverse wave from the rest position. In a longitudinal wave, this is the maximum distance moved by an oscillating object from its equilibrium position.
• Hertz (Hz)


  Unit of frequency.
• Kilohertz (Khz)


  Another unit of frequency. 1 kHz = 1000 Hz.
• Speed


  How fast an object is travelling. Often represented by 'v'.
• Metres Per Second (m/s)


  The unit of speed and velocity.
• Period


  The time for one cycle of a wave, measured in seconds. Often represented by 'T'.
• Electromagnetic Waves


  Electric and magnetic disturbances that transfer energy from one place to another.
• Electromagnetic Spectrum


  List of electromagnetic waves which shows the different types of electromagnetic waves as their wavelength changes.
• Vacuum


  An area or space which is entirely empty and contains no matter.
• Radio Waves


  Electromagnetic waves with a wavelength longer than about 10 cm. These are electromagnetic waves with the lowest energy.
• Microwaves


  Electromagnetic waves with a wavelength between approximately 1 mm and 10 cm.
• Infrared Radiation


  Electromagnetic waves between visible light and microwaves in the electromagnetic spectrum.
• Visible Light


  Electromagnetic waves that can be seen by the human eye.
• Ultraviolet Radiation


  Electromagnetic waves between visible light and X-rays in the electromagnetic spectrum.
• X-Rays


  Electromagnetic waves between ultra violet and gamma rays in the electromagnetic spectrum. They are commonly used for medical imaging.
• Gamma Radiation


  Electromagnetic waves with the shortest wavelengths and the highest energy in the electromagnetic spectrum.
• Reflection


  When a wave bounces off of the surface of a substance.