A pair of narrow, parallel slits separated by $0\mathrm{.}266$ mm are illuminated by the green LED laser $(=546\mathrm{.}1nm).$ The interference pattern is observed on a screen $1\mathrm{.}40$ m from the plane of the parallel slits.

$($a$)$ Calculate the distance from the central maximum to the first bright region.

What is the relationship between the slit separation, wavelength, and bright fringe distance? m

$($b$)$ What is the distance between the first and second dark fringes?

$q,$

What is the relationship between the slit separation, wavelength, and dark fringe distance? m