Question

What should be the width of each slit to obtain 10 maxima of the double slit pattern within the central maximum of the single slit pattern?

Answer 1

aθ = λ

where

a is the slit width

θ is the angular separation and

λ is the wavelength

so,

θ = λ/a

now, in this case we have

width of each slit = width of ten maxima

so,

10(λ/d) = 2(λ/a)

or

a = d/5

thus, the slit width will be

a = 1/5 = 0.2 mm

Answer 2

In Young's double slit experiment the separation d between the slits is 2mm, the wavelength λ of light used is 5896Ao and distance D between the screen and slits is 100cm. It is found that the angular width of the fringes is 0. 20o. To increase the fringe angular width to 0.