Wave Properties

• A wave could be defined as any disturbance which moves along a medium, repeating itself in any one position in that medium at regular intervals.
• A medium is any material substance which can propagate waves or energy.
• Waves are produced by oscillation or vibrations.
• Oscillations that repeat at regular intervals are described as periodic.
• There are two types of waves: Transverse waves, in which the medium vibrates at right angles to the direction of its propagation, and do not require a medium to propagate, and Longitudinal waves, in which the medium vibrates in the direction of its propagation, and do require a medium to propagate.
• Examples of Transverse waves include electromagnetic waves.
• Examples of Longitudinal waves include sound waves.
• Wave characteristics include Peak or Crest, the highest point of a wave, Trough, the lowest point of a wave, Wavelength, λ, the distance between two consecutive points on a wave which are in phase, Amplitude, A, the distance between the center of the wave and the crest or trough, Frequency, f, the number of oscillations (or cycles) there are per second, and Period, T, the time it takes to complete one oscillation (or cycle).
• Two or more points on a wave are exactly in phase if the disturbance on the wave is at the same stage at those points.
• Amplitude is the distance between the center of the wave and the crest or trough.
• Frequency is the number of oscillations (or cycles) there are per second.
• Period is the time it takes to complete one oscillation (or cycle).
• Speed of a wave, v, is the distance travelled by a given point on the wave in a given time interval.
• Wave Speed, v, is the speed of light, c, times the wavelength, λ, v = c λ; units = ms -1.
• Light is also a wave and travels at a certain speed, the speed of light in a vacuum, c = 3.0 x 10 8 ms -1.
• Light is an electromagnetic wave and all electromagnetic waves travel at the speed of light.