Monochromatic light $($ $=670$ nm$)$ is incident on a single slit and forms a diffraction pattern on a screen $95$ cm away. $($a$)$ If the slit width is $0\mathrm{.}04$ mm$,$ what is the separation between the first$-$order minima $($y $11)?($b$)$ If the slit width is reduced by half, what now is $$y $11?$