The condition for observing Fraunhofer diffraction from a single slit is that the light wavefront incident on the slit should be

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

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.

To observe diffraction,the size of an obstacle:

If $I_0$ is the intensity of the principal maximum in the single slit diffraction pattern,then what will be the intensity when the slit width is doubled?

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)