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24 Cards in this Set
- Front
- Back
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Transverse Wave
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Particles displaced (oscillations) perpendicular to direction of travel
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Longitudinal Wave
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Particles displaced (oscillations) parallel to direction of travel
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Stationary Waves
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Superposition of 2 progressive waves with same frequency and amplitude moving in opposite directions
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Nodes Anti-Nodes |
Zero displacement Maximum displacement |
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First Harmonic |
Order 1 No Overtone 1 half wavelength 1 antinode |
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Second Harmonic
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Order 2 First Overtone 1 wave 2 antinodes Frequency 2x first harmonic |
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Third Harmonic
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Order 3 Second Overtone 1.5 waves 2 antinodes Frequency 3x first harmonic |
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Factors affecting Resonant Frequency
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Longer the string, lower the resonant frequency Heavier the string, lower the resonant frequency Lower the tension, lower the resonant frequency |
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Diffraction Gaps
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Larger the gap, the more unnoticeable the diffraction Gap same size as wavelength lots of diffraction Gap smaller then wavelength waves reflected back |
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Monochromatic Light
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single wavelength (frequency)
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Coherent
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Same wavelength, frequency and a fixed phase difference between them
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Diffraction of Monochromatic Light (single slit) |
Bright central fringe 2x width Alternating dark and bright fringes Less intense as go away from centre |
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Diffraction of White Light (single slit) |
Different wavelengths diffract different amounts White central fringe Alternating rainbow and dark fringes blue light closer to central fringe and red far away from middle |
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Width of Central Maximum
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Increasing slit width decreases diffraction central maximum is narrower but more intense Increasing wavelength increases amount of diffraction central maximum is wider but less intense |
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Intensity
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Power per unit area
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Path Difference
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Amount one wave has travelled is longer by another wave
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Constructive Interference Destructive Interference (Two-Source Interference) |
Maxima equal distance from both sources or whole wavelength path difference Minima path differene is half a wavelength |
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Optical Fibres
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High refractive index cores Low refractive index cladding Allows for TIR Cladding prevents scratching on fibres allowing light to escape Cladding prevents crossover of 2 wires Carries more information as light has higher frequency Doesn't heat up fibre Cheaper No electrical interference |
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Signal Degradation by Absorption
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Some signal energy absorbed by material in fibre reducing amplitude of signal |
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Signal Degradation by Pulse Broadening
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Recieved signal is broader so can overlap each other losing some infomation Modal Dispersion Material Dispersion |
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Modal Dispersion
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Light rays enter at different angles so one has to travels a longer distance so takes longer
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Material Dispersion
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Different amount of dispersions experienced by different wavelengths of length as white line is used
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Fix Signal Degregation
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Optical fibre repeaters can be used to regenerate the signal
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Passing Polarisation Filters over each other
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Intensity from light to dark over 90 degrees block lights |
