IGCSE Physics\General Properties of Waves\Important Concepts
IGCSE PHYSICS
GENERAL PROPERTIES OF WAVES: IMPORTANT CONCEPTS
A wave is a disturbance which transfers energy from one point to another without
transfer of matter between the points.
Two types of progressive waves:
(a) Transverse waves: waves in which the direction of disturbance (i.e. direction of
vibration of particles) is perpendicular to the direction of propagation of energy
(i.e. direction of travel of wave)
(b) Longitudinal waves: waves in which the direction of disturbance (i.e. direction
of vibration of particles) is parallel to the direction of propagation of energy
(i.e. direction of travel of wave)
Illustration of transverse and longitudinal waves using a slinky coil:
(a) Transverse wave:
Crests (peaks) and troughs (valleys) represent the points with maximum perpendicular
displacement from the equilibrium position
(b) Longitudinal wave:
Rarefactions and compressions represent the points with minimum and maximum pressures
respectively
Examples of transverse and longitudinal waves:
Transverse waves Longitudinal waves
WAVE MOTION AND FEATURES
For analysis of wave motion, two different graphs can be used:
(a) Displacement-position (displacement-distance) graph: A plot of the
displacement of wave particle from equilibrium position against the position
along the path of the wave (i.e. the distance from wave source) at a particular
instant.
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, IGCSE Physics\General Properties of Waves\Important Concepts
(b) Displacement-time graph: A plot of the displacement of one wave particle from
its equilibrium position against time.
For analysis of water waves using a ripple tank, waves are created by a vibrating
dipper with a light source placed above the tank. Bright and dark fringes, each
representing the crests and troughs of the waves respectively, are formed.
crest crest
direction
of equilibrium
vibration position
trough
Important wave terms:
(a) Amplitude, a: The maximum displacement of a wave particle from its
equilibrium position (i.e. undisturbed position); given by the height of a crest or
the depth of a trough.
(b) Wavelength, : The distance between two adjacent points on a wave which are
in the same phase of motion; given by the distance between two adjacent
crests or troughs.
(c) Wavefront: The imaginary line that joins all the points on a wave which have
the same phase of motion; given by the line that joins all the crests (or
troughs) which are at the same distance from the source of the wave.
A line source generates plane wavefronts, while a point source generates
circular wavefronts.
_____________________________________________________________________________
Nakazawa EduServ. Created by Jackson Tik, B.Sc. (NUS). ©All rights reserved.
2
IGCSE PHYSICS
GENERAL PROPERTIES OF WAVES: IMPORTANT CONCEPTS
A wave is a disturbance which transfers energy from one point to another without
transfer of matter between the points.
Two types of progressive waves:
(a) Transverse waves: waves in which the direction of disturbance (i.e. direction of
vibration of particles) is perpendicular to the direction of propagation of energy
(i.e. direction of travel of wave)
(b) Longitudinal waves: waves in which the direction of disturbance (i.e. direction
of vibration of particles) is parallel to the direction of propagation of energy
(i.e. direction of travel of wave)
Illustration of transverse and longitudinal waves using a slinky coil:
(a) Transverse wave:
Crests (peaks) and troughs (valleys) represent the points with maximum perpendicular
displacement from the equilibrium position
(b) Longitudinal wave:
Rarefactions and compressions represent the points with minimum and maximum pressures
respectively
Examples of transverse and longitudinal waves:
Transverse waves Longitudinal waves
WAVE MOTION AND FEATURES
For analysis of wave motion, two different graphs can be used:
(a) Displacement-position (displacement-distance) graph: A plot of the
displacement of wave particle from equilibrium position against the position
along the path of the wave (i.e. the distance from wave source) at a particular
instant.
_____________________________________________________________________________
Nakazawa EduServ. Created by Jackson Tik, B.Sc. (NUS). ©All rights reserved.
1
, IGCSE Physics\General Properties of Waves\Important Concepts
(b) Displacement-time graph: A plot of the displacement of one wave particle from
its equilibrium position against time.
For analysis of water waves using a ripple tank, waves are created by a vibrating
dipper with a light source placed above the tank. Bright and dark fringes, each
representing the crests and troughs of the waves respectively, are formed.
crest crest
direction
of equilibrium
vibration position
trough
Important wave terms:
(a) Amplitude, a: The maximum displacement of a wave particle from its
equilibrium position (i.e. undisturbed position); given by the height of a crest or
the depth of a trough.
(b) Wavelength, : The distance between two adjacent points on a wave which are
in the same phase of motion; given by the distance between two adjacent
crests or troughs.
(c) Wavefront: The imaginary line that joins all the points on a wave which have
the same phase of motion; given by the line that joins all the crests (or
troughs) which are at the same distance from the source of the wave.
A line source generates plane wavefronts, while a point source generates
circular wavefronts.
_____________________________________________________________________________
Nakazawa EduServ. Created by Jackson Tik, B.Sc. (NUS). ©All rights reserved.
2
