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_{s}) in a window shade, admitting a narrow sliver of sunlight into a dark room. He inserted a colored filter into the sunbeam that transmitted a narrow band [tex]\Delta[/tex][tex]\lambda[/tex] of wavelengths around a center wavelength [tex]\lambda[/tex]

_{0}. A distance L

_{s}away, the filtered beam illuminated an opaque screen in which he had cut 2 identical slits, each of width w, seperated by distance d > w. He observed the interference pattern on a screen located distance L beyond the slits.

L

_{s}= 2 m

w = 0.1mm

d = 0.25 mm

[tex]\lambda[/tex]

_{0}= 0.5 microns

L = 4 m

r = radius of pattern (or screen needed)

Here is what I did, and my results seem too small.

[tex]\theta[/tex] = 1.22([tex]\lambda[/tex]/d) = r/L

Solving for r I got:

r = 1.22(L[tex]\lambda[/tex]/d) = 4.88 mm

Like I said, this doesn't seem correct. It seems like the entire pattern will spread out more. How can I determine the width of the pattern?