A monochromatic light beam of wavelength λ is diff
e iq*wsxh:q- kh2gh m7(lma(,racted at a single slit of width
i *h-hm,wq(a:2 g mhksxq 7le($b$. After passing the slit, a diffraction pattern is observed on a screen a large distance away. The width of the central maximum is $w$.
The screen is moved closer to the slit. Which of the following changes, done separately, could result in no change in $w$?