We have not covered in class yet and the book does not offer much help. Is it asking for the value (m)? If so how is that determined? Thanks.
Light of wavelength 616 nm (in vacuum) is incident perpendicularly on a soap film (assume n = 1.36) suspended in the air. What are the two smallest nonzero film thicknesses (in nm) for which the reflected light undergoes constructive interference?
(a) ___nm (smallest thickness)
(b) ___nm (next smallest thickness)© BrainMass Inc. brainmass.com October 16, 2018, 5:32 pm ad1c9bdddf
This is a standard physics problem. Sometime they ask about reflected light, sometimes transmitted light. ...
This solution contains an annotated diagram and step-by-step explanations of wave concepts to determine the nonzero film thickness for which reflected light undergoes constructive interference.
Thin film interference and air gap of variable thickness
** Please see the attached file for the complete problem description **
Say you saw the following interference pattern due to air between two glass slides:
(please see the attached file)
a) What can you say about the thickness of the air gap across the slide? Is it uniform? What does it mean if there isn't any color (e.g., over their finger near the top right of the image)? What does it mean if there are lots of lines? Etc.
b) What is the requirement on the thickness of the film for constructive interference in this case? Consider the relative indices of refraction involved?
c) How can you determine the thickness of the air gap at a particular location? Derive an equation to use in the lab. Be explicit about your assumptions. Don't assume normal incidence.View Full Posting Details