Module 2 - Waves Flashcards
Amplitude
The maximum displacement of a wave from its resting position, measured in metres.
Absorption spectrum
A spectrum of dark lines across the pattern of spectral colours produced when light passes through a gas and the gas absorbs certain frequencies depending on the elements in the gas.
Antinode
A point of maximum amplitude along a stationary wave. (m)
Coherence
Two waves with a Constant phase relationship.
Diffractio
When a wave spreads out after passing around an obstacle or through a gap.
Emission spectrum
A pattern of colours in light, each colour having a specific wavelength.
Frequency
The number of oscillations per unit time, measured in hertz
Fundamental frequency
The lowest frequency in a harmonic series where a stationary wave forms.
Harmonics
Whole number multiples of the fundamental frequency of a stationary wave.
Intensity
The energy incident per unit square metre of a surface per second, measured in warts per metre squared.
Line spectrum
Spectrum produced by a material that contains only certain frequencies due to electron transitions between energy levels.
Longitudinal wave
A wave where the oscillations are parallel to the direction of the wave propagation, e.g. Sound
Malus’ law
A physical law describing the change in intensity of the transfers waves passing through a Polaroid analyser.
Monochromatic light
Light waves with a single frequency (or wavelength).
Period (T)
The time taken for one complete a pattern of oscillation, measured in seconds.
Phase difference
The difference by which one wave leads or lags behind another. For example in phase waves are in step with each other. In ways that are completely out phase 1 wave is half a wavelength in front of the other. Measured in radians.
Plane polarised wave
A transverse wave oscillating in only one plane.
Polarisation
The process of turning an unpolarised wave into a plane polarised wave (for example, light passing through a polarised filter).
Progressive wave
A wave that travels from one place to another
Radian
An angle or phase difference.
One radian is equal to the angle subtended at the centre of a circle by an arc of circumference.
Spectral line
Aligned relating to specific frequency either missing from absorption spectrum or present in an emission spectrum.
Spectrum
A collection of waves with a range of frequencies for example, spectrum and electromagnetic spectrum.
Standing/stationary wave
A wave formed by the interference of two waves travelling in opposite directions.
Superposition
The principal states that when waves of the same type exist at the same place the resultant wave will be found by adding the displacement of each individual wave.
