Thin-film interference
Variant i Dynamics first
Students are led to develop a functional understanding of thin-film interference they can use to solve problems about thin-film interference without relying on memorized equations.
Topics Waves and optics / Physical optics: models, representations, periodic circular waves, wave front diagrams, and physical optics
Materials
Materials by the UW team
- Instructor Guide
- Pretest
- Exam Questions
- Equipment List
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Tutorial details
The tutorial begins with a review of a previous tutorial, Reflection and transmission. Students recall the circumstances under which a periodic wave on a spring undergoes a phase change upon reflection from a surface. They also review the result that although the wavelength changes on transmission into a second medium, the frequency does not. Students then make an analogy between this situation and a beam of light incident on a soap film. A series of questions leads students step-by-step through the reasoning necessary to determine whether a thin soap film of uniform thickness illuminated by monochromatic light at normal incidence will appear bright, dark, or in between. Later in the tutorial, students consider a film of non-uniform thickness and go through the reasoning necessary to determine the appearance of the film as a whole.
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Prerequisites
Prerequisite tutorials
The Reflection and transmission of pulses and Two-source interference tutorials are prerequisites to Thin-film interference.
Other prerequisites
Students should have worked through the tutorials Reflection and transmission and Two-source interference.
Coming Soon! We hope to release the discussion section on each tutorial soon.
