- #1
Isaac Pepper
- 31
- 1
Homework Statement
A thin piece of metal foil of thickness 0.0700 mm separates one end of two pieces of optically flat glass. The top sheet of glass is 12.0 cm long. Light of wavelength 529 nm is normally incident on the glass. How many interference fringes are observed per cm in the reflected light?
Homework Equations
##\lambda = \frac{\lambda_0}{n}##
##2t = m\lambda## constructive or destructive depending on phase shift (where t is the thickness 0.0700mm)
##2t = (m+\frac{1}{2})\lambda##
maybe some other equations..I'm not sure!
The Attempt at a Solution
I'm not really sure how to come about solving this problem, and any help would be greatly appreciated.
I don't know if I've understood the question correctly, but I'm thinking there's just a piece of metal separating two pieces of glass, and light coming in normal to the surface of the glass?
Since the refractive index of the glass is less than that of the metal foil there will be no phase shift, and then there will be a phase shift between the foil and the next piece of glass.
Am I on the right track or am I looking at it completely the wrong way?
Thanks !