A monochromatic light beam of wa
;licncb-;zsmee h53(velength λ is diffracted at a single slit of width
s5 ;lhe(n3eciz c-;bm$b$. 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 $w$?