A
Amplitude - The amplitude of a wave is the height
of a crest from the undisturbed position. See Just Waves Hard Section for more information.
Antinode - The point on a wave of greatest
displacement.
C
C - The speed of light. A fixed
constant - 3x108ms-1 - beyond which nothing of
mass can be accelerated. This principle is used extensively in Einstein's Special
Theory of Relativity.
CRO - Cathode Ray Oscilloscope. A laboratory
instrument used in the measurement and study of waves.
D
Diaphragm - A thin membrane that converts sound
energy to electrical energy.
Diffraction - This occurs when waves pass through a
gap or round an object of roughly the same size, or smaller than their wavelength, and then spread out.
E
Electromagnetic Waves - These waves are not sound,
although people often use them to transmit sound information such as using radio waves.
These all have the same speed, which is c
(The speed of light). Light, Microwaves and Infa-red are also part of the
electromagnetic spectrum.
F
First Harmonic - The smallest standing wave that
can fit on a string or in a pipe.
Frequency - This is the number of waves which pass
a fixed point in one second. F=1/T where T is the time
period of the wave.
I
Interference - This occurs when two or more sets of
waves meet and either constructively interfere to reinforce each other or destructively
interfere to cancel each other out.
L
Longitudinal Waves - Vibrations are in the same
direction as the plane of motion. See Just Waves Hard Section for more information.
N
Natural Frequency - The frequency at which an
object will vibrate freely when set in motion.
O
Ossicles - See Hearing Page.
P
p.d. - Potential Difference or Voltage.
Pitch - A notes pitch depends on its frequency. The pitch of a note becomes higher as the
frequency increases. See Maths & Music for more
information.
Polarisation - A wave is polarised when all the
vibrations are absorbed except those in one plane.
R
Resonance - If the natural
frequency of an oscillator is equal to the frequency of a driver in a forced
oscillations system, then resonance will occur.
S
Standing Waves - A wave which appears to remain
still as it is reflected at both ends.
T
Time period - The length of time required for one
wave to pass a fixed point.
Transverse Waves - Vibrations are at right angles
to the direction of the wave. See Just Waves Hard section for more information.
W
Wavelength - The distance between one crest and the
next. See Just Waves Hard section for more information.
