Wedge interference - solving for 'separation of fringes' without lambda

[iffybom]

Homework Statement

plane plates of glass are in contact along one side and held apart by a wire 0.05mm in diameter, parallel to the edge in contact and 20cm distant. using filtered green mercury light, directed normally on the air film between plates, interference fringes are seen. calculate the separation of dark fringes. how many fringes appear between the edge and the wire?

Homework Equations

t=x*theta=m*(lambda/2)
delta x = x*(lambda/(2*t))

The Attempt at a Solution

i've been using ratio and proportion here since theta will remain constant. however, i cannot get to cancel out lambda nor m. is it necessary to solve for the wavelength of 'filtered green mercury light' first, so everything else will be plug and chug?

 

[rl.bhat]

Yes. Without the wave length you cannot find the fring width.

 

[kerimek]

I would approach this problem by first determining the wavelength of the "filtered green mercury light" using a spectrometer or other appropriate instrument. This will give you a more accurate value to use in your calculations.

Once you have the wavelength, you can use the equations provided to solve for the separation of dark fringes and the number of fringes between the edge and the wire. It may also be helpful to draw a diagram of the setup to better visualize the situation and identify any other relevant variables.

Additionally, you may want to consider the effects of the wire's diameter on the interference pattern, as it may cause diffraction and affect the spacing of the fringes. Overall, it is important to carefully consider all relevant variables and use appropriate equations and techniques to accurately solve for the desired quantities.