In a two-slit setup, each slit is 0.02 mm wide. these apertures are illustrated by plane waves of sodium light (wavelength = 589.6 nm). the resulting fringe pattern consists of 11 narrow fringes that gradually decrease in intensity with distance from the central maximum. determine the separation between the slits.,

d = 0.22 mm

Explanation:

The phenomenon of interference and diffraction is always present, the latter is the envelope that modulates the process, let's write the equation of each

Interference       d sin θ = m λ

Diffraction          a sin θ = n λ

Where d is the separation between the slits, a is the width of each, n and m are integers

In general, the most intense diffraction order is the first, so we can do n = 1, divide the two equations

    d sin θ/ a sin θ = m λ / λ

    d / a = m

They give us the number of interference lines (m = 11), the width of each slit (a = 0.02 mm) and the wavelength (λ = 589.6 nm), let's calculate

            d = a m

            d = 0.02 11

            d = 0.22 mm

does anyone know or what?