In a single slit diffraction pattern,identify the incorrect statement from the following.

The condition for diffraction is

The diffraction of light starts from an obstacle (edge). It depends on ...

Assertion : Diffraction takes place for all types of waves,mechanical or non-mechanical,transverse or longitudinal.
Reason : Diffraction effects are perceptible only if the wavelength of the wave is comparable to the dimensions of the diffracting device.

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

Light of wavelength $\lambda = 5000 \ \mathring{A}$ falls normally on a narrow slit. $A$ screen is placed at a distance of $1 \ m$ from the slit and perpendicular to the direction of light. The first minima of the diffraction pattern is situated at $5 \ mm$ from the centre of the central maximum. The width of the slit is ....... $mm$.