Homework Statement
A single slit diffracts laser light of wavelength 650 nm onto a screen 2.00 m away. The distance between the two first-order maxima on either side of the central peak is 2.05 mm. How wide is the slit?
Homework Equations
a=width of slit
y=distance from central max to specific...
Everything you are doing is correct. You have but one problem at the end though. You are probably typing it in your calculator wrong.
0.5 = cos^2 (9617.1204 * θ)
According to my calculator θ = 0.03743 deg
0.5 = cos^2 (9617.1204 * θ)
sqrt(0.5) = cos (9617.1204 * θ)
cos^-1(sqrt(.5))=9617.1204θ...