Waves 0.0 / 5 PhysicsWavesA2/A-levelAQA Created by: Pops!Created on: 07-02-17 11:37 Wave Motion Oscillations can produce waves, which carry energy Energy ccarried in a wave depends on its amplitude Energy is directly proportional to amplitude squared Frecuency is related to the period f=1/T Wavelength, frequency and speed of wave are related v=f Phase difference gives difference between similar points on two waves - measured in degrees/radians TRANSVERSE - oscillations at right angles to direction in which wave is moving Can be polarised (by removing all components exept those in plane of oscillation) LONGITUDINAL - oscillations in same direction that wave is moving Can't be polarised As a wave spreads out, its intensity decreases by an inverse-square law I=P/4r2 1 of 4 Reflection & Refraction Angle of incidence = angle of refraction i=r n = refactive index n=sini/sinr refractive index of a medium = speed of light in a vacuum/speed of light in the medium n1sin1 = n2sin2 when light moves from one medium to another n=1/sinc c = critical angle If the angle of incidence in an opticaly more dense medium is greater than the critical angle TOTAL INTERNAL REFLECTION takes place 2 of 4 Interference Principle of superposition = when 2 or more waves meet, the resultant displacement is found by adding the displacements together Waves interfere constructively IN PHASE Waves interfere destrucively in ANTIPHASE When waves reflect forwards and backwards, they superimpose and form a stationary wave Stationary waves have nodes and anti-nodes (distance between adjacent nodes = 1/2) Stationary waves have certain definite frequencies at which it will resonate First harmonic of stretched wire - 3 of 4 Diffraction When waves pass through a gap, they diffract - narrow gaps cause more spreading Young's double slit experiment has 2 slits at distance s apart, which give a pattern of maxima and minima viewed from a distance of D away The separation between adjacent maxima = w so... A diffraction grating gives a sharper, brighter maxima than Young's experiment The diffraction grating equation is: for the nth-order maximum 4 of 4

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