Question

A beam of light of λ = 600 nm from a distant source falls on a single slit 1 mm wide and the resulting diffraction pattern is observed on a screen 2 m away. The distance between first dark fringes on either side of the central bright fringe is

(a) 1.2 cm

(b) 1.2 mm

(c) 2.4 cm

(d) 2.4 mm

Answer 1

Correct option  (d) 2.4 mm

Explanation:

Here, λ = 600 nm = 600 x 10^-9 m

a = 1 mm=10^-3 m,D=2 m

Distance between the first dark fringes on either side of the central bright fringe is also the width of central maximum.