The angular width of the central maximum in a single-slit diffraction pattern does not depend on .........

In a single slit diffraction pattern:

Light of wavelength $550\, nm$ falls normally on a slit of width $22.0 \times 10^{-5}\, cm$. The angular position of the second minima from the central maximum will be (in radians)

$A$ slit of width $a$ is illuminated by red light of wavelength $6500 \, \mathring{A}$. The first minimum will fall at $\theta = 30^{\circ}$ if $a$ is equal to:

In Fraunhofer diffraction due to a single slit,find the path difference for the $n^{th}$ order minimum.

Two wavelengths of sodium light $590 \,nm$ and $596 \,nm$ are used one after another to study diffraction due to a single slit of aperture $2 \times 10^{-6} \,m$. The distance between the slit and the screen is $1.5 \,m$. The separation between the positions of the first maximum of the diffraction pattern obtained in the two cases is: (in $\,mm$)