Answer:
Explanation:
Given
slit width [tex]d=0.0549\ mm[/tex]
wavelength of light [tex]\lambda =735\ nm[/tex]
Screen is placed at a distance of [tex]D=2.85\ m[/tex]
The angle for the first minima is given by
[tex]\sin \theta _1=\frac{m\lambda }{d}[/tex]
for m=1
[tex]\sin \theta _1=\frac{1\times 735\times 10^{-9}}{0.0549\times 10^{-3}}[/tex]
[tex]\sin \theta _1=0.0133[/tex]
and one half of central maxima is given by
[tex]Y=D\sin \theta _1[/tex]
[tex]Y=2.85\times 0.0133[/tex]
[tex]Y=0.0381\ m[/tex]
Width of central maxima [tex]=2Y[/tex]
[tex]Width=0.0762\ m\approx 7.62\ cm[/tex]