3.1.1

oscillation of the particles of the medium

progressive waves: waves which travel through a substance or through space if electromagnetic

amplitude: distance from the equilibrium to maximum displacement or minimum displacement, measured in metres (m)
frequency: the number of cycles of a wave that pass a point in 1 second, measured in Hertz (Hz) (F=1/T)

wavelength: the least distance between two adjacent vibrating particles with the same displacement and velocity at the same time (e.g. distance between two adjacent peaks), measured in metres (m)

displacement: distance from the equilibrium position, measured in metres (m)

time period: time for one complete wave cycle, measured in seconds (s)

wave speed = frequency x wavelength (c=f𝜆)
measured in metres per second (ms^-1)

phase: the position of a point in time on a wave cycle

phase difference: the fraction of a cycle between the vibrations of two vibrating particles, measured either in radians or degrees, or as fractions of a cycle

two sources are IN PHASE if both waves are at the same point in their cycles at the same time

two sources are in ANTIPHASE if both waves are at exactly opposite points in their cycles at the same time

two sources are OUT OF PHASE if the waves are at different points in their cycles at the same time

if the phase difference is an odd number of 𝜋 radians, the waves are in antiphase

if the phase difference is an even number of 𝜋 radians, the waves are in phase