Which of the following waves exhibits clear diffraction?

In a single-slit diffraction experiment,if the width of the slit is reduced,what happens to the linear width of the principal (central) maxima?

$A$ screen is placed at a certain distance from a narrow slit,which is illuminated by a parallel beam of monochromatic light. What will you observe if you scan the screen with the help of a microscope?

$A$ linear aperture whose width is $0.02\, cm$ is placed immediately in front of a lens of focal length $60\, cm.$ The aperture is illuminated normally by a parallel beam of wavelength $5 \times 10^{-5}\, cm.$ The distance of the first dark band of the diffraction pattern from the centre of the screen is .....$cm$

$A$ single slit diffraction pattern is formed with white light. For what wavelength of light, the $3^{\text{rd}}$ secondary maximum in the diffraction pattern coincides with the $2^{\text{nd}}$ secondary maximum in the pattern of red light of wavelength $6000 \text{ Å}$ (in $\text{ Å}$)?

$A$ parallel beam of monochromatic light falls normally on a single narrow slit. The angular width of the central maximum in the resulting diffraction pattern