$A$ diffraction pattern is obtained by using a beam of red light. What will happen if the red light is replaced by blue light?

In the far-field diffraction pattern of a single slit under polychromatic illumination,the first minimum with the wavelength ${\lambda _1}$ is found to be coincident with the third maximum at ${\lambda _2}$. So,

The condition for obtaining secondary maxima in the diffraction pattern due to a single slit is:

In a diffraction pattern due to a single slit of width $a$,the first minimum is observed at an angle $30^{\circ}$ when light of wavelength $5000 \; \mathring{A}$ is incident on the slit. The first secondary maximum is observed at an angle of

$A$ parallel beam of monochromatic light of wavelength $5000 \mathring{A}$ is incident normally on a single narrow slit of width $0.001 \text{ mm}$. The light is focused by a convex lens on a screen placed on its focal plane. The first minima will be formed for the angle of diffraction of . . . . . . (degree).

Assertion: $A$ coloured spectrum is seen when we look through a muslin cloth.
Reason: It is due to the diffraction of white light on passing through fine slits.