A monochromatic light beam of wavelength λ is dif
/1zsb s :5/ikwm i8qxlh8ss*bfracted at a single slit of widt
/bs *h5qss/z:ms8xk18w biil 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 $w$?