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20 Cards in this Set
- Front
- Back
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Wavefront |
A line representing points on a wave that are all in phase |
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Superposition |
The combination of displacements of two similar waves when they meet at a point Resultant displacement = vector sum of displacement of the two waves |
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(1) Constructive interference (2) Destructive interference |
(1) Two waves pass each other in phase => displacements add to create larger wave (2) Two waves pass each other completely out of phase => displacements cancel to create zero displacement |
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Coherent |
The light source has the same frequency, λ and a fixed phase difference |
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Stationary (standing) wave |
Stores energy rather than transferring it |
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Progressive wave |
Transfers energy from one point to another without transferring matter |
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How is a standing wave formed on a string? |
(1) A wave is reflected from a closed end => 2 waves travelling in opposite directions down same string (2) Where the waves meet in phase => constructive interference (antinode) Where waves meet in antiphase => destructive interference (node) |
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(1) Node (2) Antinode |
(1) Point of minimum displacement (no movement from equilibrium position) (2) Point of maximum displacement |
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Difference between progressive and standing waves [3] |
(1) Store energy (2) Vary in amplitude from zero --> maximum (3) Oscillations in phase between nodes |
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Properties of fundamental frequency |
1st harmonic Length = λ / 2 |
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Properties of third harmonic |
2nd overtone Length = 3/2 λ |
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Equation for speed of a transverse wave on a string |
v = √ T / μ |
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Frequency of a wave on a string |
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Intereference |
When waves from two coherent sources overlap to produce a pattern of maxima and minima |
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Diffraction |
= The spreading out of waves after passing through a gap > Maximum when λ = size of slit |
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Huygens’ construction |
= Every point on a wavefront is a point source of secondary wavelets which spread out to form the next wavefront |
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Young's double slit experiment |
--> to support theory of wave nature of light (1) Laser (monochromatic) light shone through double slit and diffracts (2) Interference pattern of maxima and minima (fringes) shown on screen |
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Slit equation |
λ = Sx / D wavelength = slit width x fringe separation / distance from slit to screen |
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Why does light diffract less than sound when passing through a door? |
> λ of light much smaller compared to size of doorway, whereas sound λs more similar in size |
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Diffraction grating equation |
nλ = d sin θ n = order of maximum d = slit separation |
