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Answer
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Define amplitude
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Maximum displacement of the medium from equilibrium
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Define frequency
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The number of wave cycles per second OR the number of waves passing a point per second
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Define time period
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Time for one complete wave cycle
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What is the relationship between frequency and time period?
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f = 1/T or inverse proportionality
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Describe a transverse wave
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Displacement/oscillation of medium/particles is perpendicular to the direction of wave propagation
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What is meant by coherent sources of waves
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Same frequency and constant phase difference.
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Describe the principle of superposition
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When two or more waves meet the total displacement is the (vector) sum of the displacements of the individual waves.
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Give an example of longitudinal waves
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Sound, primary seismic waves
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Give an example of transverse waves
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Waves on a plucked string, secondary seismic waves, electromagnetic radiation
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Describe plane polarised light
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Electromagnetic waves with oscillations in a single direction perpendicular to wave propagation
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Describe unpolarised waves
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Waves with oscillations in many directions perpendicular to wave propagation.
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Which waves can't be polarised?
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Longitudinal waves
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What is the phase difference between points quarter a wavelength apart?
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Pi/2 radians OR 90'
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What is the phase difference between waves in antiphase
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Pi radians OR 180'
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Describe the effect of a polarising filter
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Only transmits the component of the wave oscillating parallel to the polarising filter
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Describe the effect of two polarising filters perpendicular to each other
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No light is transmitted
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Give a use of polarising filters
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Reducing glare in sunglasses and camera, 3D TV, LCD screens,
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Light reflected from a shiny surface is
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partially polarised
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Light scattered is
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polarised
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Define oscillation
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A displacement one way and then the other about an equilibrium position.
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Define displacement (waves)
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Measures how far a particle is from its equilibrium position.
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Define propagation
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Describes the motion of a wave through a medium/space
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Define a mechanical wave
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Requires a medium to travel in
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What is µ in f = (1/2L)×√(T/µ)
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Mass per unit length of the string kgm⁻¹
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