points in phase

points in a wave that have the same displacement and are moving in the same direction.

B and E

C and D

B and D are OUT of phase

wavelength

distance between two successive points in phase

BE and CD

**Unit**: meters or m

amplitude

maximum distance a point moves from it’s rest position

AB

**Unit**: meters or m

frequency

number of complete vibrations that occur in one second

**Symbol**: f

**Unit**: hertz or Hz

period

time taken for one complete vibration to occur

**Symbol**: T

**Unit**: seconds or s

wave front

line joining points in the same phase

eg: a line joining all the points on a crest of a wave

velocity

rate of change of displacement

**Symbol**: v

**Unit**: ms^{-1}

transverse wave

disturbance at right angles to direction of propagation of the wave

longitudinal wave

disturbance in the direction of propagation of the wave