A monochromatic light beam
,zs/g gig36bjdmt :b(m+ po)n of wavelength λ is diffracted at a single slit of widt
:mjbon z6isb3tdg,(/g)+p gmh $b$. 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 $w$?