A monochromatic light beam of wavelength λ is diffrac
blt oi go)lm 4og/.3/sted at a single slit of width
o/i3om) gb4s.lo /glt $b$. 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 $w$?