(3.0) - Wave Definitions Flashcards
What is Amplitude?
A wave’s maximum displacement from its equilibrium position.
What is an Antinode?
A position of maximum displacement in a stationary wave.
What is Cladding?
A protective layer on an optical fibre to improve tensile strength, prevent scratching, and prevent signal transfer between adjacent fibres.
What is Coherence?
Waves are coherent if they have the same wavelength and frequency, with a fixed phase difference between them.
What is a Diffraction Grating?
A grating with hundreds of slits per millimetre, resulting in sharper interference patterns.
What is Diffraction?
The spreading of waves as they pass through a gap of a similar magnitude to their wavelength.
What are Electromagnetic Waves?
Waves that consist of perpendicular electric and magnetic oscillations.
What is Frequency?
The number of waves that pass a point in a unit time period; it is the inverse of the time period.
What is Fringe Spacing?
The distance between two adjacent bright fringes or two adjacent dark fringes.
What is Interference?
The superposition of waves that occurs when two waves meet, leading to constructive or destructive interference.
What is a Laser?
A light source that produces a collimated and coherent beam.
What is a Longitudinal Wave?
A wave with oscillations that are parallel to the direction of energy propagation.
Sound waves are an example of a longitudinal wave.
What is Material Dispersion?
Waves of different wavelengths travel at slightly different speeds through an optical fibre, causing pulse broadening.
What is Modal Dispersion?
Waves enter an optical fibre at slightly different angles, causing them to reach the end at different times and leading to pulse broadening.
What is a Node?
A position of minimum displacement in a stationary wave.
What is an Optical Fibre?
A thin glass fibre through which signals are passed. Optical fibres usually have cladding surrounding them.
What is Path Difference?
A measure of how far ahead a wave is compared to another wave, usually expressed in terms of the wavelength.
What is Phase Difference?
The difference in phase between two points on a wave, usually expressed in radians.
What is Phase?
A measure of how far through the wave’s cycle a given point on the wave is.
What is Polarisation?
The restriction of a wave so that it can only oscillate in a single plane, applicable only to transverse waves.
What is Pulse Broadening?
The elongation of a signal passed down an optical fibre, commonly due to modal or material dispersion.
What is Refractive Index?
A material property equal to the ratio between the speed of light in a vacuum and the speed of light in a given material.
What is Snell’s Law?
A law linking a wave’s angle of incidence to its angle of refraction, using the refractive indexes of the mediums involved.
What is Speed in terms of waves?
The product of a wave’s frequency and wavelength.
What is a Stationary Wave?
A wave that stores, but does not transfer, energy.
What is Total Internal Reflection?
An effect in optical fibres where full reflection occurs at the inside boundary of the fibre, preventing radiation from passing out.
What is a Transverse Wave?
A wave with oscillations that are perpendicular to the direction of energy propagation.
Electromagnetic waves are examples of transverse waves.
What is Wavelength?
The distance between two identical positions on two adjacent waves, commonly measured from peak to peak or trough to trough.
What is Young’s Double-Slit Experiment?
An experiment demonstrating the diffraction of light by passing monochromatic light across two narrow slits and observing the resulting pattern of bright and dark fringes.
