$A$ slit of width $a$ is illuminated by monochromatic light of wavelength $650 \ nm$. The value of the slit width $a$ when the first minimum is formed at a diffraction angle of $30^\circ$ is:

Determine the angular separation between the central maximum and the first-order maxima of the diffraction pattern due to a single slit of width $0.25\, mm$ when light of wavelength $5890\,\mathring{A}$ is incident on it.

$A$ screen is placed at $50 \ cm$ from a single slit,which is illuminated with light of wavelength $600 \ nm$. If the separation between the $1^{st}$ and $3^{rd}$ minima in the diffraction pattern is $3 \ mm$,then the slit width is: (in $mm$)

The first diffraction minimum due to the single slit diffraction is seen at $\theta = 30^o$ for a light of wavelength $5000 \,\mathring{A}$ falling perpendicularly on the slit. The width of the slit is

Visible light of wavelength $6000 \times 10^{-8} \; cm$ falls normally on a single slit and produces a diffraction pattern. It is found that the second diffraction minimum is at $60^{\circ}$ from the central maximum. If the first minimum is produced at $\theta_{1}$,then $\theta_{1}$ is close to.....$^{\circ}$

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