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f=1/T
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v=fλ
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λ=c/f
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v=λ/T
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constructive p.d (antinode) = nλ
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'loud', 'light band'
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or nλ = |S₁X-S₂X|
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destructive p.d (node) = (n-0.5)λ
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'quiet', 'dark band'
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or (n-0.5)λ = |S₁X-S₂X|
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one free end, one fixed (odd):
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λ=4L/n, f=nv/4L
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fixed ends:
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λ=2L/n, f=nv/2L
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fringe spacing:
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∆x=λL/d
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bigger Δx gives more refraction, more spread out
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Δx=fringe spacing (m), λ=wavelength (m), L=distance from slits to screen (m), d=slit separation (m)
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refraction & reflection:
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n=c/v
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where; n=speed of light in a vacuum/ speed of light medium
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n₁v₁=n₂v₂
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diffraction∝λ/w
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n₁sin(θ₁)=n₂sin(θ₂)
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energy∝frequency
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n₁sin(θ₁)=n₂
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Young’s double slit experiment shows light exhibiting the wave properties of diffraction and interference.
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Light can be polarised, observed as white light diffracts and colours are seen as a result. As only transverse waves can be polarised, the wave model of light is proven.
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Transverse waves: particle moves along vertical axis
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Longitudinal waves: particle moves along horizontal axis
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Coherent waves: waves with the same frequency
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Mechanical (sound, air, water) waves do not exist in a vacuum, they require a medium to travel through
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Electromagnetic (light) waves can exist in a vacuum, do not require a medium
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Travelling wave: a wave for which the crests and troughs travel in the direction of wave propagation.
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Standing Waves: when 2 wave trains with the same amplitude and wavelength move through each other, the resulting interfering pattern results in a standing wave. Consists of alternating nodes and antinodes that remain in a fixed position, wave appears to be stationary/'standing'
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fundamental frequency: n=1
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Waves reflect at the end of a string and are inverted if end is fixed
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An object or system will resonate if driven at its natural frequency
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Resonance greatly increases magnitude of oscillation in an object/system
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Doppler effect is the detected frequency change due to the relative motion between a wave source and detector.
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f increases when source and detector move towards each other
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f decreases when source and detector move away from each other
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independent: variable that is being changed (x-axis)
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dependent: variable that is being measured (y-axis)
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Cheatography n. The art of mapping complex subjects into clear, instantly navigable reference guides.
