Interference II Pt I

  1. 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 waves
    • How these waves travel relative to each other
  2. 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 
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    • sources not the medium
    • Φ1 and Φ2 are the phases of the waves
  3. 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
  4. The speakers are ______ wavelength(s) apart so the crests are ______. 
    What does the superposition look like? and what is Δd?
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    • one 
    • aligned
    • Superposition a wave with larger amplitude 
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  5. 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 
    • coincides
    • in phase
    • constructively
    • ΔΦ = 2πm
  6. The individual waves are ____ _____ and therefore are indistinguishable. They also exhibit ________ interference (explain) 
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    • in phase
    • constructive interference (amplitudes add)
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  7. 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
  8. The speakers are ____ wavelength apart so crests meet _______. The superposition is a wave with _____ amplitude. What is Δd?
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    • 1/2 wavelength apart
    • troughs 
    • zero amplitude
    • Δd is the path-length difference 
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  9. 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?
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    • 0
    • troughs 
    • destructively
    • cancel
    • 180° out of phase
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    • m = 0, 1, 2, 3,...
  10. 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
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  11. 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)
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    • ΔΦ0 = 0
    • when Δx = mλ (when the path-length difference is an integer number of wavelength)
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  12. In a Perfect destructive interference state the formula for:
    ΔΦ 
    ΔΦ0 (for identical sources)
    Δx (explain)
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  13. What are three ways of achieving destructive interference
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    • (Path difference)/(wavelength) = Δx/λ
    • whole number results (0, ±1, ±2, ±3...)are constructive interference and half numbers are destructive interference
    • a) (6-2)/4 = 1 aka constructive
    • b) (5-3)/4 = 1/2 aka destructive
    • c) (4-4)/4 = 0 aka constructive
    • d) (3-5)/4 = -1/2 aka destructive
    • e) (2-6)/4 = -1 aka constructive
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  17. What are the 3 Models of Light?
    (define each)
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  18. 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 light
    • ray 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 space
    • 2) It is a simplification model
  19. 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
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    • perpendicular
    • straight line
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  20. Case 1: λ<<d
    In the Ray Model, in Geometric Optics, define:
    λ
    d

    The individual waves emerging from the opening continue to move in a _____ _____. Good for the study of mirrors, lenses, prisms, and associated optical instruments 
    Label the diagram 
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    • λ: wavelength of the ray
    • d: the diameter of the opening or barrier
    • straight line
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  21. Case 2: λ ~ d
    The waves spread out from the opening in ____ ______. The waves undergo _______
    Label the diagram:
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    • all directions
    • diffraction
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  22. Case 3: λ>>d
    The diffraction is so great that the opening can be approximated as a ______ ______. Light _____ ____ behind the slit
    • point source
    • spreads out
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  23. 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) 
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  24. 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 frequency
    • When a wave passes into another medium, its speed changes, but its frequency does not.
  25. 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 = λf
    • frequency 
    • wavelength (λ)
  26. 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
    • frequency
    • changes
    • wavelength
  27. 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
  28. This is a transparent material in which light travels ______, at speed v = ____.
    The wavelength inside the material ________, but the frequency does not
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    • slower 
    • v = c/n
    • decreases
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  29. Define Monochromatic, coherent and incoherent
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  30. 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 ________
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  31. 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
  32. To observe interference in light waves, what two conditions must be met:
    • The sources should be monochromatic
    • The sources must be coherent
  33. 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 ______ ______
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    • double slit
    • spread out
    • whole number 
    • whole number 
    • half 
    • central maximum
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  34. 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 
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Author
chikeokjr
ID
345641
Card Set
Interference II Pt I
Description
Interference II Pt I
Updated