Slit width in milimeters

Question

Light of wavelength 502 nanometers passes through a double slit aperture. The first non-central bright spot is located at 2.88 degrees. What is the slit width in millimeters?

Answer 1

This looks like you need to use the formula

 

mλ = d sinθ

 

m = order = 1 in this problem

λ = wavelength = 502 x 10^-9 m

d = separation distance between slits

θ = angle associated with the order m, which is 2.88° in this problem

 

d = mλ / sinθ = (1)(502 x 10^-9 m) / sin(2.88º) = 9.99 x 10^-6 m = 9.99 μm

 

d = 9.99 x 10^-3 mm