Light of wavelength 633 nm from a distant source is incident on a slit 0.750 mm wide, and the resulting diffraction pattern is observed on a screen 3.50 m away. what is the distance between the two dark fringes on either side of the central bright fringe?

y=5.908 mm

Explanation:

Given data

wavelength (λ)= 633nm

d(distant source is incident on a slit)=0.750mm

D(diffraction pattern is observed on a screen)=3.50 m

To find

y(What is the distance between the two dark fringes on either side)=?

Solution

For a dark fringe to form

dy/D=λ

so

y=(Dλ)/deq(1)

Put values of D,λ and d in eq(1) we get

y={3.50×(633×10⁻⁹)}/(0.750×10⁻³)

y=2.954mm

So the total distance between dark fringes on either side is 2×y

so final distance is

y=5.908 mm