Answer:
30 mm
Explanation:
[tex]\lambda[/tex] = Wavelength of light = 503 nm
d = Diameter of hole = 0.2 mm
D = Distance of screen from light source = 4.9 m
Diameter of the central bright area is given by
[tex]x=\dfrac{2.44\lambda D}{d}\\\Rightarrow x=\dfrac{2.44\times 503\times 10^{-9}\times 4.9}{0.2\times 10^{-3}}\\\Rightarrow x=0.03\ \text{m}=30\ \text{mm}[/tex]
The diameter of the central bright area is 30 mm.
