Waves Definitions Flashcards
(28 cards)
Amplitude
The maximum displacement of a vibrating particle or wave from its equilibrium
position.
Antinode
The point on a stationary wave where the incoming and reflected wave are in
phase forming a maximum point.
Coherence
Waves with the same frequency and constant phase difference.
Constructive Interference:
Interference when the two waves are in phase. If the two waves
are both at their peak the addition of the two peaks becomes large.
Converging Lens:
A lens that takes a parallel set of light rays and causes them to meet at a
point.
Destructive Interference:
nterference when the two waves are in antiphase. When one
wave is at a peak and one is at a trough their addition results in a minimum point.
Diffraction
The spread of a wave as it passes through a gap or over an edge.
Focal Length:
The distance from the centre of the lens to the focal point.
Focal Point:
The point at which rays of light passing through a lens converge (or appear to
converge).
Fundamental Frequency:
The oscillation of an entire object forming the lowest possible
frequency for that object. For a string fixed at both ends this is where there is only a single
antinode in the middle of the string.
Huygen’s Principle:
Every point on a wavefront can be treated as a point source of a
secondary wavelet.
Ionisation
When an electron is removed from an atom giving the atom a positive charge.
In-Antiphase:
When the phase difference between two waves is 180 degrees or π radians.
In-Phase:
When the phase difference between two waves is 0 degrees or 0 radians.
Intensity
The power transferred by a wave per unit area
Lens Power:
: The inverse of the focal length.
Longitudinal Wave:
A wave whose oscillations are parallel to the direction of propagation of
the wave (e.g. sound waves).
Magnification:
The height of an object divided by the height of its image.
Node
The point on a stationary wave where the incoming and reflected wave are in
antiphase forming a minimum point.
Path difference
For two waves starting from different points and arriving at the same point
the path difference is the difference in the length travelled by each wave, measured in
metres.
Phase difference
The difference in phase if the phase of two waves is determined at a
single point in time, measured in radians or degrees. It can be seen as the amount by which
one wave lags behind another.
Pulse-echo technique
An ultrasound technique used for imaging of objects notably in
medical imaging. Short pulses of ultrasound are sent through a medium and their reflections
recorded.
Real image
Where rays of light have actually converged to produce an image and can be
projected onto a screen.
stationary wave
A wave that stores energy instead of transferring it. A common example is
a string fixed at both ends. They are formed by a wave propagating and being reflected so
that it comes into superposition with itself.
