A monochromatic light beam of wavelength λ is diff
(fmdb*lw9.y.r+fyef2 wha3 eracted at a single slit of width
b e3w yreylf.aw+29fmdf *h(. $b$. 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 $w$?