In a single slit diffraction experiment, the width of the slit is made double the original width. How does this affect the size and intensity of the central diffraction band.

Explanation

The size reduces to half according to the relation size `=(lambda)/9d),` where `d=2d' and` size = half the original size. The angular size of central maximum
`theta=(n lambda)/(d)` and intensity of central maximum is proportional to `cos^2 theta`.
As d increases, `theta` decreases. For `lt theta 90^@, cos gt 0.`
Hence the intensity of light increases four fold.