# Interference II Pt I

 16.5 Interference in One Dimension  Two traveling waves can pass through each other without being ______ or ______. A consequence of the ________ principle.  Define Interference What two factors do the amplitude of the resultant wave depend on? destroyed or altered superposition principle Interference: when two or more waves are superimposed on each other, and combine to form a single resultant wave Depends on:The amplitudes of the combining wavesHow these waves travel relative to each other Assume the 2 waves are sinusoidal, have the same ______ and ______, and travel to the right along the x axis, state the formula for D1 and D2. Φ10 and Φ20 are characteristics of the _____, not the ______ What do Φ1 and Φ2 represent same frequency and amplitude  sources not the mediumΦ1 and Φ2 are the phases of the waves If crest meets crest, and trough meets  trough, we say that the waves are ____ ____ with each other.  Φ1 = ___ or Φ1 = _______, where m is an integer. Their amplitudes will _____, and we say the waves interfere ______.  The amplitude of the resultant pulse is _______ than either individual pulse in phase Φ1 = Φ2 or Φ1 = Φ2±2πm add interfere constructively greater than The speakers are ______ wavelength(s) apart so the crests are ______.  What does the superposition look like? and what is Δd? one alignedSuperposition a wave with larger amplitude  When Φ1 = Φ2 or Φ1 = Φ2±2πm, where m = 0, 1, 2, 3,... The amplitude of the resultant wave is ____. The crests of one wave ______ with the crests of the other wave. The waves are in _____ everywhere. The waves interfere ________ (state the formula for ΔΦ) 2a coincidesin phaseconstructivelyΔΦ = 2πm The individual waves are ____ _____ and therefore are indistinguishable. They also exhibit ________ interference (explain)  in phaseconstructive interference (amplitudes add) When can we say waves are out of phase (180° or π radian out of phase) with each other? Their amplitudes ______ and we say the waves interfere ______. The amplitude of the resultant pulse is ______ than either individual pulse 180° or π radian out of phase: If the crest of one wave coincides with the trough of the other (and vice versa) subtract interfere destructively less than The speakers are ____ wavelength apart so crests meet _______. The superposition is a wave with _____ amplitude. What is Δd? 1/2 wavelength aparttroughs zero amplitudeΔd is the path-length difference  The amplitude of the resultant wave is ____. Crests of one wave coincide with ______ of the other wave. The waves interfere ________ so the waves ______. The individual waves are ____ ____ ____ ____. Label the diagram and what is the formula for ΔΦ and its m series? 0troughs destructivelycancel180° out of phasem = 0, 1, 2, 3,... Restate the formula for Φ1 and Φ2. Then state the formula for phase difference (3) and specify the meaning of the components of its final formula For maximum constructive interference:  State the formula for ΔΦ (2) rad where m = 0, 1, 2, 3,... For identical sources, ie. ΔΦ0 = ___, when does maximum constructive interference occur? (explain) ΔΦ0 = 0when Δx = mλ (when the path-length difference is an integer number of wavelength) In a Perfect destructive interference state the formula for: ΔΦ  ΔΦ0 (for identical sources) Δx (explain) What are three ways of achieving destructive interference (Path difference)/(wavelength) = Δx/λwhole number results (0, ±1, ±2, ±3...)are constructive interference and half numbers are destructive interferencea) (6-2)/4 = 1 aka constructiveb) (5-3)/4 = 1/2 aka destructivec) (4-4)/4 = 0 aka constructived) (3-5)/4 = -1/2 aka destructivee) (2-6)/4 = -1 aka constructive What are the 3 Models of Light? (define each) Geometric optics involves the study of the ______ ____ _____. The _____ ______ is used to represent beams of light.  Define a ray and state 2 of its uses propagation of lightray approximation Ray: a straight line drawn along the direction of propagation of a single wave 1) it shows the path of the wave as it travels through space2) It is a simplification model The rays are straight lines _______ to the wave fronts. With the ray approximation, we assume that a wave moving through a medium travels in a ______ ______ in the directions of its rays. Label the diagram perpendicularstraight line Case 1: λ<>d The diffraction is so great that the opening can be approximated as a ______ ______. Light _____ ____ behind the slit point sourcespreads out Light wave travels with speed c in a vacuum, but they _____ _____ as they pass through transparent materials. The speed of light in a material is characterized by the material's ______ ____ ______ (__) (state the formula) What changes for n in a vacuum vs in other media? slow down index of refraction (n)  What are the Two Big Rules for Waves The speed of a wave is determined by the type of wave and the characteristics of the medium, not by the frequencyWhen a wave passes into another medium, its speed changes, but its frequency does not. Referring back to rule #1 The speed of a wave is determined by the type of wave and the characteristics of the medium, not by the frequency. Since v = ___ and the wave speed is NOT dependent on _______. Therefore, if frequency changes, it only affects the ________ (__), not v v = λffrequency wavelength (λ) Referring back to rule #2 When a wave passes into another medium, its speed changes, but its frequency does not. Frequency of a wave is the ________ of the source. In different medium, the wave speed ______. Thus, the wave will undergo a different ________ in different medium frequencychangeswavelength As light travels from one medium to another, its _______ remains constant. Since v varies from one medium to another, this implies _______ varies.  State the formula for λmedium frequency wavelength λmedium = λvacuum/n This is a transparent material in which light travels ______, at speed v = ____. The wavelength inside the material ________, but the frequency does not slower v = c/ndecreases Define Monochromatic, coherent and incoherent The superposition principle allows us to add up ______ ______ by adding their ___ and ___ fields Define Constructive and Destructive  For light to display interference, it must be ________ In constructive interference, the amplitude of the resultant wave is ______ than that of either individual wave. In destructive interference, the amplitude of the resultant wave is _____ than that of either individual wave greater less To observe interference in light waves, what two conditions must be met: The sources should be monochromaticThe sources must be coherent A plane wave is incident on the _______ _____ Waves _____ ____ behind each slit Constructive interference occurs when r1 and r2 differ by a _____ ______ of wavelengths Destructive interference occurs when r1 and r2 differ by a _____ _____ of wavelengths plus _____ a wavelength The bright fringes are labeled by the integer m, starting at the ______ ______ double slitspread outwhole number whole number half central maximum Most cases, d << L → θ is ______ Thus, we can use small angle approximation:  sin θ ~ _____ ~ _____ State the formula for Path difference Δr (2) tan θ y small Authorchikeokjr ID345641 Card SetInterference II Pt I DescriptionInterference II Pt I Updated2019-03-13T21:23:05Z Show Answers