Waves Flashcards
Amplitude
A wave’s maximum displacement from its equilibrium position.
Antinodes
Antinodes: A position of maximum displacement in a stationary wave.
Coherence
Waves with the same frequency and constant phase difference.
Constructive interference
The type of interference that occurs when two waves meet in phase. The wave amplitudes are superposed.
Critical angle
The angle of incidence that results in an angle of refraction of exactly 90o . It is when the refracted ray travels along the boundary line.
Destructive interference
The type of interference that occurs 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 spreading of waves as they pass through a gap of a similar magnitude to their wavelength.
Displacement
The distance that a point on a wave is from its equilibrium position.
Electromagnetic Spectrum
The spectrum of electromagnetic waves, consisting of Gamma Rays, X-Rays, Ultraviolet, Visible Light, Infrared, Microwaves and Radiowaves.
Electromagnetic waves
Waves that consist of perpendicular electric and magnetic oscillations. All electromagnetic waves travel at the speed of light in a vacuum.
Frequency
The number of waves that pass a point in a unit time period. It is the inverse of the time period.
Fundamental Mode of Vibration
The oscillation of a wave at its natural frequency.
Intensity
The power transferred per unit area. It is proportional to the square of a wave’s amplitude.
Interference
The superposition of the amplitudes of waves when they meet.
Longitudinal Waves
A wave with oscillations that are parallel to the direction of energy propagation. Sound waves are an example of a longitudinal wave. They cannot travel through a vacuum.
Nodes
A position of minimum displacement in a stationary wave.
Oscilloscope
A device used to display and analyse waveforms.
Path Difference
A measure of how far ahead a wave is compared to another wave, usually expressed in terms of the wavelength.
Period
The time taken for a wave to complete one full cycle.
Phase Difference
The difference in phase between two points on a wave. It is
usually expressed in radians
Polarisation
The restriction of a wave so that it can only oscillate in a single plane. This can only occur for transverse waves.
Progressive Waves
Waves that transfer energy from one point to another without a transfer of matter.
Reflection
The bouncing of a wave at a boundary. The angle of incidence will equal to the angle of reflection.
Refraction
The changing of speed of a wave as it passes into a new medium. If it passes into an optically denser medium, it will slow down.
Refractive Index
A material property that is equal to the ratio between the speed of light in a vacuum, and the speed of light in a given material
Stationary Wave
A wave that stores, but does not transfer, energy.
Superposition
When two waves meet at the same point in space their displacements combine and the total displacement at that point becomes the sum of the individual displacements at that point.
Total Internal Reflection
An effect that occurs in optical fibres, where full reflection occurs at the inside boundary of the fibre, meaning no radiation passes out. The angle of incidence must be greater than the critical angle for this to occur.
Transverse Waves
A wave with oscillations that are perpendicular to the direction of energy propagation. Electromagnetic waves are examples of transverse waves.
