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Problem 37.10: Thin film, variable wavelength of light

The animation shows a right-traveling light wave (shown in blue) incident on a region composed of an unknown index of refraction embedded in air (position is given in arbitrary units). The left-traveling wave (shown in red above it) represents the sum of all reflections of the incident wave at the boundaries. Notice that the wave amplitude varies with the medium in order to conserve energy.

Observe how the intensity of light transmitted through the medium changes by using the slider to change the wavelength of incident light. Note: Because the data points are connected, you must move the slider slowly to obtain a smooth curve. Restart.

  1. Why are there numerous transmission peaks?
  2. What is the index of refraction of the material?
  3. Mathematically prove that the transmission peaks must be spaced farther apart as the wavelength increases.
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